diff --git a/src/aircraft.h b/src/aircraft.h
index 3a7a99a2de..9acc5b672c 100644
--- a/src/aircraft.h
+++ b/src/aircraft.h
@@ -44,6 +44,8 @@ enum class VehicleAirFlag : uint8_t {
 
 	HelicopterDirectDescent = 3, ///< The helicopter is descending directly at its destination (helipad or in front of hangar)
 };
+
+/** Bitset of \c VehicleAirFlag elements. */
 using VehicleAirFlags = EnumBitSet<VehicleAirFlag, uint8_t>;
 
 static const int ROTOR_Z_OFFSET         = 5;    ///< Z Offset between helicopter- and rotorsprite.
diff --git a/src/airport.h b/src/airport.h
index 3b231dc286..11e2c34be3 100644
--- a/src/airport.h
+++ b/src/airport.h
@@ -56,6 +56,7 @@ enum class AirportMovingDataFlag : uint8_t {
 	Hold, ///< Holding pattern movement (above the airport).
 };
 
+/** Bitset of \c AirportMovingDataFlag elements. */
 using AirportMovingDataFlags = EnumBitSet<AirportMovingDataFlag, uint16_t>;
 
 /** Movement States on Airports (headings target) */
@@ -129,6 +130,8 @@ enum class AirportBlock : uint8_t {
 	Zeppeliner       = 62, ///< Block for the zeppeliner disaster vehicle.
 	AirportClosed    = 63, ///< Dummy block for indicating a closed airport.
 };
+
+/** Bitset of \c AirportBlock elements. */
 using AirportBlocks = EnumBitSet<AirportBlock, uint64_t>;
 
 /** A single location on an airport where aircraft can move to. */
@@ -163,6 +166,8 @@ public:
 		Helicopters = 1, ///< Can helicopters land on this airport type?
 		ShortStrip  = 2, ///< This airport has a short landing strip, dangerous for fast aircraft.
 	};
+
+	/** Bitset of \c Flag elements. */
 	using Flags = EnumBitSet<Flag, uint8_t>;
 
 	AirportFTAClass(
diff --git a/src/base_consist.h b/src/base_consist.h
index aefa55c5c6..a1997fed8f 100644
--- a/src/base_consist.h
+++ b/src/base_consist.h
@@ -28,6 +28,8 @@ enum class VehicleFlag : uint8_t {
 	ServiceIntervalIsPercent = 9, ///< Service interval is percent.
 	DrivingBackwards = 10, ///< Vehicle is driving backwards.
 };
+
+/** Bitset of \c VehicleFlag elements. */
 using VehicleFlags = EnumBitSet<VehicleFlag, uint16_t>;
 
 /** Various front vehicle properties that are preserved when autoreplacing, using order-backup or switching front engines within a consist. */
diff --git a/src/blitter/32bpp_sse2.hpp b/src/blitter/32bpp_sse2.hpp
index 93d1c7c438..679982aa0e 100644
--- a/src/blitter/32bpp_sse2.hpp
+++ b/src/blitter/32bpp_sse2.hpp
@@ -63,6 +63,7 @@ public:
 		NoAnim, ///< The sprite has no palette animated pixel.
 	};
 
+	/** Bitset of \c SpriteFlag elements. */
 	using SpriteFlags = EnumBitSet<SpriteFlag, uint8_t>;
 
 	/** Data stored about a (single) sprite. */
diff --git a/src/bridge.h b/src/bridge.h
index cae5ab072e..d32ea5b85d 100644
--- a/src/bridge.h
+++ b/src/bridge.h
@@ -30,6 +30,8 @@ struct BridgeSpec {
 		CustomPillarFlags, ///< Bridge has set custom pillar flags.
 		InvalidPillarFlags, ///< Bridge pillar flags are not valid, i.e. only the tile layout has been modified.
 	};
+
+	/** Bitset of \c ControlFlag elements. */
 	using ControlFlags = EnumBitSet<ControlFlag, uint8_t>;
 
 	TimerGameCalendar::Year avail_year; ///< the year where it becomes available
diff --git a/src/bridge_type.h b/src/bridge_type.h
index e0996dc001..2665d556a4 100644
--- a/src/bridge_type.h
+++ b/src/bridge_type.h
@@ -48,6 +48,8 @@ enum class BridgePillarFlag : uint8_t {
 	EdgeSW = 6, ///< Southwest edge is obstructed.
 	EdgeNW = 7, ///< Northwest edge is obstructed.
 };
+
+/** Bitset of \c BridgePillarFlag elements. */
 using BridgePillarFlags = EnumBitSet<BridgePillarFlag, uint8_t>;
 
 static constexpr BridgePillarFlags BRIDGEPILLARFLAGS_ALL{
diff --git a/src/cargo_type.h b/src/cargo_type.h
index b009480229..a9daeef56b 100644
--- a/src/cargo_type.h
+++ b/src/cargo_type.h
@@ -109,6 +109,7 @@ namespace CargoFilterCriteria {
  */
 inline bool IsValidCargoType(CargoType cargo) { return cargo != INVALID_CARGO; }
 
+/** Bitset of \c CargoType elements. */
 using CargoTypes = EnumBitSet<CargoType, uint64_t>;
 
 static constexpr CargoTypes ALL_CARGOTYPES{UINT64_MAX};
diff --git a/src/cargotype.h b/src/cargotype.h
index 54e7f2a1ca..a7cddef94c 100644
--- a/src/cargotype.h
+++ b/src/cargotype.h
@@ -65,6 +65,8 @@ enum class CargoClass : uint8_t {
 	NonPotable   = 14, ///< Non-potable / non-food / dirty.
 	Special      = 15, ///< Special bit used for livery refit tricks instead of normal cargoes.
 };
+
+/** Bitset of \c CargoClass elements. */
 using CargoClasses = EnumBitSet<CargoClass, uint16_t>;
 
 static const uint8_t INVALID_CARGO_BITNUM = 0xFF; ///< Constant representing invalid cargo
diff --git a/src/command_type.h b/src/command_type.h
index a39cc1da50..bd96b2b03c 100644
--- a/src/command_type.h
+++ b/src/command_type.h
@@ -401,6 +401,8 @@ enum class DoCommandFlag : uint8_t {
 	NoModifyTownRating, ///< do not change town rating
 	ForceClearTile, ///< do not only remove the object on the tile, but also clear any water left on it
 };
+
+/** Bitset of \c DoCommandFlag elements. */
 using DoCommandFlags = EnumBitSet<DoCommandFlag, uint16_t>;
 
 /**
@@ -422,6 +424,8 @@ enum class CommandFlag : uint8_t {
 	NoEst, ///< the command is never estimated.
 	Location, ///< the command has implicit location argument.
 };
+
+/** Bitset of \c CommandFlag elements. */
 using CommandFlags = EnumBitSet<CommandFlag, uint16_t>;
 
 /** Types of commands we have. */
diff --git a/src/core/pool_type.hpp b/src/core/pool_type.hpp
index 32db83dd40..2e70d0ddd2 100644
--- a/src/core/pool_type.hpp
+++ b/src/core/pool_type.hpp
@@ -19,7 +19,10 @@ enum class PoolType : uint8_t {
 	NetworkAdmin, ///< Network admin pool.
 	Data, ///< NewGRF or other data, that is not reset together with normal pools.
 };
+
+/** Bitset of \c PoolType elements. */
 using PoolTypes = EnumBitSet<PoolType, uint8_t>;
+
 static constexpr PoolTypes PT_ALL = {PoolType::Normal, PoolType::NetworkClient, PoolType::NetworkAdmin, PoolType::Data};
 
 typedef std::vector<struct PoolBase *> PoolVector; ///< Vector of pointers to PoolBase
diff --git a/src/direction_type.h b/src/direction_type.h
index f8e8f3e98b..7ac0e1ddfd 100644
--- a/src/direction_type.h
+++ b/src/direction_type.h
@@ -38,6 +38,7 @@ enum class Direction : uint8_t {
 /** Allow incrementing of Direction variables */
 DECLARE_INCREMENT_DECREMENT_OPERATORS(Direction)
 
+/** Bitset of \c Direction elements. */
 using Directions = EnumBitSet<Direction, uint8_t>;
 
 /** All possible directions. */
diff --git a/src/dropdown_type.h b/src/dropdown_type.h
index 3ebd4e01fc..e590e54d93 100644
--- a/src/dropdown_type.h
+++ b/src/dropdown_type.h
@@ -102,6 +102,8 @@ enum class DropDownOption : uint8_t {
 	Persist, ///< Set if this dropdown should stay open after an option is selected.
 	Filterable, ///< Set if the dropdown is filterable.
 };
+
+/** Bitset of \c DropDownOption elements. */
 using DropDownOptions = EnumBitSet<DropDownOption, uint8_t>;
 
 void ShowDropDownListAt(Window *w, DropDownList &&list, int selected, WidgetID button, Rect wi_rect, Colours wi_colour, DropDownOptions options = {}, std::string * const persistent_filter_text = nullptr);
diff --git a/src/engine_base.h b/src/engine_base.h
index 87975b35b1..fc6fb9fab9 100644
--- a/src/engine_base.h
+++ b/src/engine_base.h
@@ -30,6 +30,7 @@ enum class EngineDisplayFlag : uint8_t {
 	Shaded, ///< Set if engine should be masked.
 };
 
+/** Bitset of \c EngineDisplayFlag elements. */
 using EngineDisplayFlags = EnumBitSet<EngineDisplayFlag, uint8_t>;
 
 typedef Pool<Engine, EngineID, 64> EnginePool;
diff --git a/src/engine_type.h b/src/engine_type.h
index 54af76069f..56102e028e 100644
--- a/src/engine_type.h
+++ b/src/engine_type.h
@@ -176,6 +176,8 @@ enum class ExtraEngineFlag : uint8_t {
 	SyncReliability = 3, ///< Engine reliability will be synced with variant parent.
 	HasCab          = 4, ///< Train wagon has a cab and can lead a train when backing up, without any speed reduction.
 };
+
+/** Bitset of \c ExtraEngineFlag elements. */
 using ExtraEngineFlags = EnumBitSet<ExtraEngineFlag, uint8_t>;
 
 /**
@@ -195,6 +197,8 @@ enum class EngineMiscFlag : uint8_t {
 	NoBreakdownSmoke         = 6, ///< Do not show black smoke during a breakdown.
 	SpriteStack              = 7, ///< Draw vehicle by stacking multiple sprites.
 };
+
+/** Bitset of \c EngineMiscFlag elements. */
 using EngineMiscFlags = EnumBitSet<EngineMiscFlag, uint8_t>;
 
 /**
@@ -228,6 +232,8 @@ enum class EngineFlag : uint8_t {
 	Available        = 0, ///< This vehicle is available to everyone.
 	ExclusivePreview = 1, ///< This vehicle is in the exclusive preview stage, either being used or being offered to a company.
 };
+
+/** Bitset of \c EngineFlag elements. */
 using EngineFlags = EnumBitSet<EngineFlag, uint8_t>;
 
 /**
diff --git a/src/fileio_func.h b/src/fileio_func.h
index 264bb9677d..5caff43fba 100644
--- a/src/fileio_func.h
+++ b/src/fileio_func.h
@@ -67,6 +67,8 @@ public:
 		Scenario, ///< Scan for scenarios and heightmaps.
 		Game, ///< Scan for game scripts.
 	};
+
+	/** Bitset of \c Mode elements. */
 	using Modes = EnumBitSet<Mode, uint8_t>;
 
 	static constexpr Modes MODES_ALL = {Mode::Baseset, Mode::NewGRF, Mode::AI, Mode::Scenario, Mode::Game}; ///< Scan for everything.
diff --git a/src/gfx_type.h b/src/gfx_type.h
index a3b42b1f56..1d3fbdf6b2 100644
--- a/src/gfx_type.h
+++ b/src/gfx_type.h
@@ -256,6 +256,7 @@ enum class FontSize : uint8_t {
 };
 DECLARE_INCREMENT_DECREMENT_OPERATORS(FontSize)
 
+/** Bitset of \c FontSize elements. */
 using FontSizes = EnumBitSet<FontSize, uint8_t>;
 
 /** Mask of all possible font sizes. */
@@ -342,6 +343,7 @@ enum class ExtendedTextColourFlag : uint8_t{
 	NoShade, ///< Do not add shading to this text colour.
 	Forced, ///< Ignore colour changes from strings.
 };
+
 using ExtendedTextColourFlags = EnumBitSet<ExtendedTextColourFlag, uint8_t>; ///< Bitset of the flags of ExtendedTextColour. */
 
 /** Container for the text colour and some text colour related flags for drawing. */
diff --git a/src/group.h b/src/group.h
index 852f81ad7c..af334a4495 100644
--- a/src/group.h
+++ b/src/group.h
@@ -68,6 +68,8 @@ enum class GroupFlag : uint8_t {
 	ReplaceProtection = 0, ///< If set, the global autoreplace has no effect on the group
 	ReplaceWagonRemoval = 1, ///< If set, autoreplace will perform wagon removal on vehicles in this group.
 };
+
+/** Bitset of \c GroupFlag elements. */
 using GroupFlags = EnumBitSet<GroupFlag, uint8_t>;
 
 /** Group data. */
diff --git a/src/house.h b/src/house.h
index e41e1db53f..9bb5252ebf 100644
--- a/src/house.h
+++ b/src/house.h
@@ -45,6 +45,8 @@ enum class BuildingFlag : uint8_t {
 	IsChurch   = 6, ///< The building functions as a church, i.e. only one can be built in a town.
 	IsStadium  = 7, ///< The building functions as a stadium, i.e. only one can be built in a town.
 };
+
+/** Bitset of \c BuildingFlag elements. */
 using BuildingFlags = EnumBitSet<BuildingFlag, uint8_t>;
 
 static constexpr BuildingFlags BUILDING_HAS_1_TILE  = {BuildingFlag::Size1x1, BuildingFlag::Size2x1, BuildingFlag::Size1x2, BuildingFlag::Size2x2};
@@ -68,6 +70,8 @@ enum class HouseZone : uint8_t {
 	ClimateSubtropic = 14, ///< Building can appear in subtropical climate
 	ClimateToyland = 15, ///< Building can appear in toyland climate
 };
+
+/** Bitset of \c HouseZone elements. */
 using HouseZones = EnumBitSet<HouseZone, uint16_t>;
 
 static constexpr uint NUM_HOUSE_ZONES = to_underlying(HouseZone::TownEnd);
@@ -95,6 +99,8 @@ enum class HouseExtraFlag : uint8_t {
 	SynchronisedCallback1B = 2, ///< synchronized callback 1B will be performed, on multi tile houses
 	Callback1ARandomBits   = 3, ///< callback 1A needs random bits
 };
+
+/** Bitset of \c HouseExtraFlag elements. */
 using HouseExtraFlags = EnumBitSet<HouseExtraFlag, uint8_t>;
 
 struct HouseSpec {
diff --git a/src/house_type.h b/src/house_type.h
index 7fb0b449fa..de83e1d92b 100644
--- a/src/house_type.h
+++ b/src/house_type.h
@@ -27,6 +27,8 @@ enum class HouseRandomTrigger : uint8_t {
 	 */
 	TileLoopNorth,
 };
+
+/** Bitset of \c HouseRandomTrigger elements. */
 using HouseRandomTriggers = EnumBitSet<HouseRandomTrigger, uint8_t>;
 
 #endif /* HOUSE_TYPE_H */
diff --git a/src/industry.h b/src/industry.h
index e5e290923b..ac80820dff 100644
--- a/src/industry.h
+++ b/src/industry.h
@@ -54,6 +54,8 @@ enum class IndustryControlFlag : uint8_t {
 	ExternalProdLevel = 3,
 	End, ///< End marker.
 };
+
+/** Bitset of \c IndustryControlFlag elements. */
 using IndustryControlFlags = EnumBitSet<IndustryControlFlag, uint8_t, IndustryControlFlag::End>;
 
 /**
diff --git a/src/industry_type.h b/src/industry_type.h
index a563d6f5d4..9c1908b192 100644
--- a/src/industry_type.h
+++ b/src/industry_type.h
@@ -27,6 +27,8 @@ enum class IndustryRandomTrigger : uint8_t {
 	IndustryTick, ///< The industry has been triggered via its tick.
 	CargoReceived, ///< Cargo has been delivered.
 };
+
+/** Bitset of \c IndustryRandomTrigger elements. */
 using IndustryRandomTriggers = EnumBitSet<IndustryRandomTrigger, uint8_t>;
 
 /** Animation triggers of the industries. */
@@ -37,6 +39,8 @@ enum class IndustryAnimationTrigger : uint8_t {
 	CargoReceived, ///< Trigger when cargo is received .
 	CargoDistributed, ///< Trigger when cargo is distributed.
 };
+
+/** Bitset of \c IndustryAnimationTrigger elements. */
 using IndustryAnimationTriggers = EnumBitSet<IndustryAnimationTrigger, uint8_t>;
 
 static const IndustryType NUM_INDUSTRYTYPES_PER_GRF = 128;            ///< maximum number of industry types per NewGRF; limited to 128 because bit 7 has a special meaning in some variables/callbacks (see MapNewGRFIndustryType).
diff --git a/src/industrytype.h b/src/industrytype.h
index 87021da477..b091b83372 100644
--- a/src/industrytype.h
+++ b/src/industrytype.h
@@ -26,6 +26,8 @@ enum class IndustryLifeType : uint8_t {
 	Organic = 1, ///< Like forests
 	Processing = 2, ///< Like factories
 };
+
+/** Bitset of \c IndustryLifeType elements. */
 using IndustryLifeTypes = EnumBitSet<IndustryLifeType, uint8_t>;
 
 static constexpr IndustryLifeTypes INDUSTRYLIFE_BLACK_HOLE{}; ///< Like power plants and banks
@@ -79,6 +81,8 @@ enum class IndustryBehaviour : uint8_t {
 	CargoTypesUnlimited = 18, ///< Allow produced/accepted cargoes callbacks to supply more than 2 and 3 types
 	NoPaxProdClamp = 19, ///< Do not clamp production of passengers. (smooth economy only)
 };
+
+/** Bitset of \c IndustryBehaviour elements. */
 using IndustryBehaviours = EnumBitSet<IndustryBehaviour, uint32_t>;
 
 /** Flags for miscellaneous industry tile specialities */
@@ -86,6 +90,8 @@ enum class IndustryTileSpecialFlag : uint8_t {
 	NextFrameRandomBits = 0, ///< Callback 0x26 needs random bits
 	AcceptsAllCargo = 1, ///< Tile always accepts all cargoes the associated industry accepts
 };
+
+/** Bitset of \c IndustryTileSpecialFlag elements. */
 using IndustryTileSpecialFlags = EnumBitSet<IndustryTileSpecialFlag, uint8_t>;
 
 /** Definition of one tile in an industry tile layout */
diff --git a/src/landscape_type.h b/src/landscape_type.h
index d9091c9992..5dfb26790c 100644
--- a/src/landscape_type.h
+++ b/src/landscape_type.h
@@ -19,6 +19,8 @@ enum class LandscapeType : uint8_t {
 	Tropic = 2, ///< Landscape with distinct rainforests and deserts,
 	Toyland = 3, ///< Landscape with funky industries and vehicles.
 };
+
+/** Bitset of \c LandscapeType elements. */
 using LandscapeTypes = EnumBitSet<LandscapeType, uint8_t>;
 
 static constexpr uint NUM_LANDSCAPE = 4;
@@ -33,6 +35,8 @@ enum class BorderFlag : uint8_t {
 	NorthWest, ///< Border on North West.
 	Random, ///< Randomise borders.
 };
+
+/** Bitset of \c BorderFlag elements. */
 using BorderFlags = EnumBitSet<BorderFlag, uint8_t>;
 
 static constexpr BorderFlags BORDERFLAGS_ALL = BorderFlags{BorderFlag::NorthEast, BorderFlag::SouthEast, BorderFlag::SouthWest, BorderFlag::NorthWest}; ///< Border on all sides.
diff --git a/src/linkgraph/linkgraph_type.h b/src/linkgraph/linkgraph_type.h
index f9a8888a5e..9a5d428a37 100644
--- a/src/linkgraph/linkgraph_type.h
+++ b/src/linkgraph/linkgraph_type.h
@@ -50,6 +50,7 @@ enum class EdgeUpdateMode : uint8_t {
 	Unrestricted, ///< Use unrestricted link.
 };
 
+/** Bitset of \c EdgeUpdateMode elements. */
 using EdgeUpdateModes = EnumBitSet<EdgeUpdateMode, uint8_t>;
 
 #endif /* LINKGRAPH_TYPE_H */
diff --git a/src/linkgraph/refresh.h b/src/linkgraph/refresh.h
index bd357889aa..ac414f7b1f 100644
--- a/src/linkgraph/refresh.h
+++ b/src/linkgraph/refresh.h
@@ -33,6 +33,7 @@ protected:
 		InAutorefit, ///< Currently doing an autorefit loop. Ignore the first autorefit order.
 	};
 
+	/** Bitset of \c RefreshFlag elements. */
 	using RefreshFlags = EnumBitSet<RefreshFlag, uint8_t>;
 
 	/**
diff --git a/src/livery.h b/src/livery.h
index df1749aa0d..d217967977 100644
--- a/src/livery.h
+++ b/src/livery.h
@@ -86,6 +86,8 @@ struct Livery {
 		Primary = 0, ///< Primary colour is set.
 		Secondary = 1, ///< Secondary colour is set.
 	};
+
+	/** Bitset of \c Flag elements. */
 	using Flags = EnumBitSet<Flag, uint8_t>;
 
 	Flags in_use{}; ///< Livery flags.
diff --git a/src/newgrf.h b/src/newgrf.h
index 0f6383c2c0..1c76a98311 100644
--- a/src/newgrf.h
+++ b/src/newgrf.h
@@ -75,6 +75,7 @@ enum class GrfMiscBit : uint8_t {
 	SecondRockyTileSet = 6, ///< Enable using the second rocky tile set.
 };
 
+/** Bitset of \c GrfMiscBit elements. */
 using GrfMiscBits = EnumBitSet<GrfMiscBit, uint8_t>;
 
 enum class GrfSpecFeature : uint8_t {
@@ -110,6 +111,8 @@ enum class GrfSpecFeature : uint8_t {
 
 	Invalid = 0xFF, ///< An invalid spec feature
 };
+
+/** Bitset of \c GrfSpecFeature elements. */
 using GrfSpecFeatures = EnumBitSet<GrfSpecFeature, uint32_t, GrfSpecFeature::End>;
 
 static const uint32_t INVALID_GRFID = 0xFFFFFFFF;
diff --git a/src/newgrf_badge_type.h b/src/newgrf_badge_type.h
index e81fb6d595..2cd10a2a30 100644
--- a/src/newgrf_badge_type.h
+++ b/src/newgrf_badge_type.h
@@ -33,6 +33,8 @@ enum class BadgeFlag : uint8_t {
 
 	HasText, ///< Internal flag set if the badge has text.
 };
+
+/** Bitset of \c BridgeFlag elements. */
 using BadgeFlags = EnumBitSet<BadgeFlag, uint8_t>;
 
 using BadgeFilterChoices = std::unordered_map<BadgeClassID, BadgeID>;
diff --git a/src/newgrf_callbacks.h b/src/newgrf_callbacks.h
index cbdece5f98..ccbcd2f5bd 100644
--- a/src/newgrf_callbacks.h
+++ b/src/newgrf_callbacks.h
@@ -311,6 +311,8 @@ enum class VehicleCallbackMask : uint8_t {
 	Name          = 8, ///< Engine name
 	CustomRefit   = 9, ///< Custom refit mask
 };
+
+/** Bitset of \c VehicleCallbackMask elements. */
 using VehicleCallbackMasks = EnumBitSet<VehicleCallbackMask, uint16_t>;
 
 /**
@@ -323,6 +325,8 @@ enum class StationCallbackMask : uint8_t {
 	AnimationSpeed     = 3, ///< Customize the animation speed of the station
 	SlopeCheck         = 4, ///< Check slope of new station tiles
 };
+
+/** Bitset of \c StationCallbackMask elements. */
 using StationCallbackMasks = EnumBitSet<StationCallbackMask, uint16_t>;
 
 /**
@@ -333,6 +337,8 @@ enum class RoadStopCallbackMask : uint8_t {
 	AnimationNextFrame = 1, ///< Use a custom next frame callback
 	AnimationSpeed     = 2, ///< Customize the animation speed of the road stop
 };
+
+/** Bitset of \c RoadStopCallbackMask elements. */
 using RoadStopCallbackMasks = EnumBitSet<RoadStopCallbackMask, uint8_t>;
 
 /**
@@ -353,6 +359,8 @@ enum class HouseCallbackMask : uint8_t {
 	DrawFoundations         = 11, ///< decides if default foundations need to be drawn
 	Autoslope               = 12, ///< decides allowance of autosloping
 };
+
+/** Bitset of \c HouseCallbackMask elements. */
 using HouseCallbackMasks = EnumBitSet<HouseCallbackMask, uint16_t>;
 
 /**
@@ -361,6 +369,8 @@ using HouseCallbackMasks = EnumBitSet<HouseCallbackMask, uint16_t>;
 enum class CanalCallbackMask : uint8_t {
 	SpriteOffset       = 0, ///< Enable add sprite offset callback
 };
+
+/** Bitset of \c CanalCallbackMask elements. */
 using CanalCallbackMasks = EnumBitSet<CanalCallbackMask, uint8_t>;
 
 /**
@@ -370,6 +380,8 @@ enum class CargoCallbackMask : uint8_t {
 	ProfitCalc        = 0, ///< custom profit calculation
 	StationRatingCalc = 1, ///< custom station rating for this cargo type
 };
+
+/** Bitset of \c CargoCallbackMask elements. */
 using CargoCallbackMasks = EnumBitSet<CargoCallbackMask, uint8_t>;
 
 /**
@@ -392,6 +404,8 @@ enum class IndustryCallbackMask : uint8_t {
 	OutputCargoTypes       = 13, ///< customize the cargoes the industry produces
 	ProdChangeBuild        = 14, ///< initialise production level on construction
 };
+
+/** Bitset of \c IndustryCallbackMask elements. */
 using IndustryCallbackMasks = EnumBitSet<IndustryCallbackMask, uint16_t>;
 
 /**
@@ -406,6 +420,8 @@ enum class IndustryTileCallbackMask : uint8_t {
 	DrawFoundations    = 5, ///< decides if default foundations need to be drawn
 	Autoslope          = 6, ///< decides allowance of autosloping
 };
+
+/** Bitset of \c IndustryTileCallbackMask elements. */
 using IndustryTileCallbackMasks = EnumBitSet<IndustryTileCallbackMask, uint8_t>;
 
 /**
@@ -419,6 +435,8 @@ enum class ObjectCallbackMask : uint8_t {
 	FundMoreText       =  4, ///< additional text in fund window
 	Autoslope          =  5, ///< decides allowance of autosloping
 };
+
+/** Bitset of \c ObjectCallbackMask elements. */
 using ObjectCallbackMasks = EnumBitSet<ObjectCallbackMask, uint8_t>;
 
 /**
@@ -431,6 +449,8 @@ enum class AirportTileCallbackMask : uint8_t {
 	DrawFoundations    = 5, ///< decides if default foundations need to be drawn
 	Autoslope          = 6, ///< decides allowance of autosloping
 };
+
+/** Bitset of \c AirportTileCallbackMask elements. */
 using AirportTileCallbackMasks = EnumBitSet<AirportTileCallbackMask, uint8_t>;
 
 /**
diff --git a/src/newgrf_config.h b/src/newgrf_config.h
index 407310a75e..cab856b2c6 100644
--- a/src/newgrf_config.h
+++ b/src/newgrf_config.h
@@ -27,6 +27,8 @@ enum class GRFConfigFlag : uint8_t {
 	Reserved, ///< GRF file passed GrfLoadingStage::Reserve stage
 	Invalid, ///< GRF is unusable with this version of OpenTTD
 };
+
+/** Bitset of \c GRFConfigFlag elements. */
 using GRFConfigFlags = EnumBitSet<GRFConfigFlag, uint8_t>;
 
 /** Status of GRF */
@@ -46,6 +48,8 @@ enum class GRFBug : uint8_t {
 	UnknownCbResult = 3, ///< A callback returned an unknown/invalid result
 	VehCapacity     = 4, ///< Capacity of vehicle changes when not refitting or arranging
 };
+
+/** Bitset of \c GRFBug elements. */
 using GRFBugs = EnumBitSet<GRFBug, uint8_t>;
 
 /** Status of post-gameload GRF compatibility check */
diff --git a/src/newgrf_object.h b/src/newgrf_object.h
index 040dc5c581..5c6bb101ea 100644
--- a/src/newgrf_object.h
+++ b/src/newgrf_object.h
@@ -39,6 +39,8 @@ enum class ObjectFlag : uint8_t {
 	AnimRandomBits   = 12, ///< Object wants random bits in "next animation frame" callback.
 	ScaleByWater     = 13, ///< Object count is roughly scaled by water amount at edges.
 };
+
+/** Bitset of \c ObjectFlag elements. */
 using ObjectFlags = EnumBitSet<ObjectFlag, uint16_t>;
 
 static const uint8_t OBJECT_SIZE_1X1 = 0x11; ///< The value of a NewGRF's size property when the object is 1x1 tiles: low nibble for X, high nibble for Y.
diff --git a/src/newgrf_roadstop.h b/src/newgrf_roadstop.h
index 2a57f65a64..9e9631dd4b 100644
--- a/src/newgrf_roadstop.h
+++ b/src/newgrf_roadstop.h
@@ -55,6 +55,8 @@ enum class RoadStopDrawMode : uint8_t {
 	Overlay = 1, ///< Drive-through stops: Draw the road overlay, e.g. pavement
 	WaypGround = 2, ///< Waypoints: Draw the sprite layout ground tile (on top of the road)
 };
+
+/** Bitset of \c RoadStopDrawMode elements. */
 using RoadStopDrawModes = EnumBitSet<RoadStopDrawMode, uint8_t>;
 
 enum class RoadStopSpecFlag : uint8_t {
@@ -66,6 +68,8 @@ enum class RoadStopSpecFlag : uint8_t {
 	TramOnly = 6, ///< Only show in the tram build menu (not road).
 	DrawModeRegister = 8, ///< Read draw mode from register 0x100.
 };
+
+/** Bitset of \c RoadStopSpecFlag elements. */
 using RoadStopSpecFlags = EnumBitSet<RoadStopSpecFlag, uint8_t>;
 
 enum RoadStopView : uint8_t {
diff --git a/src/newgrf_station.h b/src/newgrf_station.h
index f610cfec8f..32fffc0022 100644
--- a/src/newgrf_station.h
+++ b/src/newgrf_station.h
@@ -116,6 +116,8 @@ enum class StationSpecFlag : uint8_t {
 	ExtendedFoundations = 4, ///< Extended foundation block instead of simple.
 	DivByStationArea = 5, ///< Divide cargo amount by station area.
 };
+
+/** Bitset of \c StationSpecFlag elements. */
 using StationSpecFlags = EnumBitSet<StationSpecFlag, uint8_t>;
 
 /** Station specification. */
@@ -168,7 +170,10 @@ struct StationSpec : NewGRFSpecBase<StationClassID> {
 		NoWires = 1, ///< Tile should NOT contain catenary wires.
 		Blocked = 2, ///< Tile is blocked to vehicles.
 	};
+
+	/** Bitset of \c TileFlag elements. */
 	using TileFlags = EnumBitSet<TileFlag, uint8_t>;
+
 	std::vector<TileFlags> tileflags; ///< List of tile flags.
 	std::vector<BridgeableTileInfo> bridgeable_info; ///< Per tile layout bridge information.
 
diff --git a/src/news_type.h b/src/news_type.h
index 0c4d36db5f..dc724f2abf 100644
--- a/src/news_type.h
+++ b/src/news_type.h
@@ -92,6 +92,8 @@ enum class NewsFlag : uint8_t {
 	Shaded, ///< News item uses shaded colours.
 	VehicleParam0, ///< String param 0 contains a vehicle ID. (special autoreplace behaviour)
 };
+
+/** Bitset of \c NewsFlag elements. */
 using NewsFlags = EnumBitSet<NewsFlag, uint8_t>;
 
 /**
diff --git a/src/object_type.h b/src/object_type.h
index ed011b2407..136814dc3a 100644
--- a/src/object_type.h
+++ b/src/object_type.h
@@ -38,6 +38,8 @@ enum class ObjectAnimationTrigger : uint8_t {
 	TileLoop, ///< Triggered in the periodic tile loop.
 	TileLoopNorth, ///< Triggered every 256 ticks (for all tiles at the same time).
 };
+
+/** Bitset of \c ObjectAnimationTrigger elements. */
 using ObjectAnimationTriggers = EnumBitSet<ObjectAnimationTrigger, uint16_t>;
 
 #endif /* OBJECT_TYPE_H */
diff --git a/src/openttd.h b/src/openttd.h
index 95425775f7..084d3719d2 100644
--- a/src/openttd.h
+++ b/src/openttd.h
@@ -78,6 +78,8 @@ enum class PauseMode : uint8_t {
 	LinkGraph          = 6, ///< A game paused due to the link graph schedule lagging
 	CommandDuringPause = 7, ///< A game paused, and a command executed during the pause; resets on autosave
 };
+
+/** Bitset of \c PauseMode elements. */
 using PauseModes = EnumBitSet<PauseMode, uint8_t>;
 
 /** The current pause mode */
diff --git a/src/order_type.h b/src/order_type.h
index 42c99a9477..06d0c32f31 100644
--- a/src/order_type.h
+++ b/src/order_type.h
@@ -89,6 +89,7 @@ enum class OrderNonStopFlag : uint8_t {
 	GoVia = 1, ///< The vehicle will stop at any station it passes except the destination, aka via.
 };
 
+/** Bitset of \c OrderNonStopFlag elements. */
 using OrderNonStopFlags = EnumBitSet<OrderNonStopFlag, uint8_t>;
 
 /**
@@ -109,6 +110,7 @@ enum class OrderDepotTypeFlag : uint8_t {
 	PartOfOrders = 1, ///< This depot order is because of a regular order.
 };
 
+/** Bitset of \c OrderDepotTypeFlag elements. */
 using OrderDepotTypeFlags = EnumBitSet<OrderDepotTypeFlag, uint8_t>;
 
 /**
@@ -120,6 +122,7 @@ enum class OrderDepotActionFlag : uint8_t {
 	Unbunch = 2, ///< Service the vehicle and then unbunch it.
 };
 
+/** Bitset of \c OrderDepotActionFlag elements. */
 using OrderDepotActionFlags = EnumBitSet<OrderDepotActionFlag, uint8_t>;
 
 /**
diff --git a/src/pathfinder/yapf/yapf_type.hpp b/src/pathfinder/yapf/yapf_type.hpp
index d284979cb8..29c17462f3 100644
--- a/src/pathfinder/yapf/yapf_type.hpp
+++ b/src/pathfinder/yapf/yapf_type.hpp
@@ -33,6 +33,8 @@ enum class EndSegmentReason : uint8_t {
 	LookAheadEnd, ///< we have just passed the last look-ahead signal
 	TargetReached, ///< we have just reached the destination
 };
+
+/** Bitset of \c EndSegmentReason elements. */
 using EndSegmentReasons = EnumBitSet<EndSegmentReason, uint16_t>;
 
 /** What reasons mean that the target can be found and needs to be detected. */
diff --git a/src/picker_gui.h b/src/picker_gui.h
index f9bd8dbe4f..01a13e9538 100644
--- a/src/picker_gui.h
+++ b/src/picker_gui.h
@@ -326,6 +326,8 @@ public:
 		Validate, ///< Validate selected item.
 		Filter, ///< Update filter state.
 	};
+
+	/** Bitset of \c Pickerinvalidation elements. */
 	using PickerInvalidations = EnumBitSet<PickerInvalidation, uint8_t>;
 
 	static constexpr PickerInvalidations PICKER_INVALIDATION_ALL{PickerInvalidation::Class, PickerInvalidation::Type, PickerInvalidation::Position, PickerInvalidation::Validate};
diff --git a/src/rail.h b/src/rail.h
index 9356a65014..08b42de46a 100644
--- a/src/rail.h
+++ b/src/rail.h
@@ -32,6 +32,8 @@ enum class RailTypeFlag : uint8_t {
 	Allow90Deg      = 4, ///< Bit number for always allowed 90 degree turns, regardless of setting.
 	Disallow90Deg   = 5, ///< Bit number for never allowed 90 degree turns, regardless of setting.
 };
+
+/** Bitset of \c RailTypeFlag elements. */
 using RailTypeFlags = EnumBitSet<RailTypeFlag, uint8_t>;
 
 struct SpriteGroup;
diff --git a/src/rail_type.h b/src/rail_type.h
index fbbc6f85e7..ef14182687 100644
--- a/src/rail_type.h
+++ b/src/rail_type.h
@@ -35,6 +35,7 @@ enum RailType : uint8_t {
 /** Allow incrementing of Track variables */
 DECLARE_INCREMENT_DECREMENT_OPERATORS(RailType)
 
+/** Bitset of \c RailType elements. */
 using RailTypes = EnumBitSet<RailType, uint64_t>;
 
 static constexpr RailTypes INVALID_RAILTYPES{UINT64_MAX};
diff --git a/src/road.h b/src/road.h
index e21fdf5452..df65bc20ad 100644
--- a/src/road.h
+++ b/src/road.h
@@ -28,6 +28,8 @@ enum class RoadTypeFlag : uint8_t {
 	Hidden          = 3, ///< Bit number for hidden from construction.
 	TownBuild       = 4, ///< Bit number for allowing towns to build this roadtype.
 };
+
+/** Bitset of \c RoadTypeFlag elements. */
 using RoadTypeFlags = EnumBitSet<RoadTypeFlag, uint8_t>;
 
 struct SpriteGroup;
diff --git a/src/road_type.h b/src/road_type.h
index 6a68a1aa8a..c00ac76748 100644
--- a/src/road_type.h
+++ b/src/road_type.h
@@ -29,6 +29,7 @@ enum RoadType : uint8_t {
 };
 DECLARE_INCREMENT_DECREMENT_OPERATORS(RoadType)
 
+/** Bitset of \c RoadType elements. */
 using RoadTypes = EnumBitSet<RoadType, uint64_t>;
 
 /**
diff --git a/src/roadstop_base.h b/src/roadstop_base.h
index 85d7028117..f3680042cd 100644
--- a/src/roadstop_base.h
+++ b/src/roadstop_base.h
@@ -26,6 +26,8 @@ struct RoadStop : RoadStopPool::PoolItem<&_roadstop_pool> {
 		BaseEntry = 6, ///< Non-zero when the entries on this road stop are the primary, i.e. the ones to delete
 		EntryBusy = 7, ///< Non-zero when roadstop entry is busy
 	};
+
+	/** Bitset of \c RoadStopStatusFlag elements. */
 	using RoadStopStatusFlags = EnumBitSet<RoadStopStatusFlag, uint8_t>;
 
 	/** Container for each entry point of a drive through road stop */
diff --git a/src/script/script_config.hpp b/src/script/script_config.hpp
index 85ab2877a6..fd8f0680ec 100644
--- a/src/script/script_config.hpp
+++ b/src/script/script_config.hpp
@@ -25,6 +25,7 @@ enum class ScriptConfigFlag : uint8_t {
 	Developer = 3, ///< This setting will only be visible when the Script development tools are active.
 };
 
+/** Bitset of \c ScriptConfigFlag elements. */
 using ScriptConfigFlags = EnumBitSet<ScriptConfigFlag, uint8_t>;
 
 typedef std::map<int, std::string> LabelMapping; ///< Map-type used to map the setting numbers to labels.
diff --git a/src/settings_internal.h b/src/settings_internal.h
index 121ef967ad..4b12938fea 100644
--- a/src/settings_internal.h
+++ b/src/settings_internal.h
@@ -30,6 +30,8 @@ enum class SettingFlag : uint8_t {
 	NoNetworkSync, ///< Do not synchronize over network (but it is saved if SettingFlag::NotInSave is not set).
 	Sandbox, ///< This setting is a sandbox setting.
 };
+
+/** Bitset of \c SettingFlag elements. */
 using SettingFlags = EnumBitSet<SettingFlag, uint16_t>;
 
 /**
diff --git a/src/signal.cpp b/src/signal.cpp
index e3c73dab20..d6b37252d7 100644
--- a/src/signal.cpp
+++ b/src/signal.cpp
@@ -262,6 +262,8 @@ enum class SigFlag : uint8_t {
 	Enter, ///< signal entering the block found
 	MultiEnter, ///< two or more signals entering the block found
 };
+
+/** Bitset of \c SigFlag elements. */
 using SigFlags = EnumBitSet<SigFlag, uint16_t>;
 
 /**
diff --git a/src/spritecache_type.h b/src/spritecache_type.h
index 3905457971..150c1eba7f 100644
--- a/src/spritecache_type.h
+++ b/src/spritecache_type.h
@@ -29,6 +29,7 @@ enum class SpriteCacheCtrlFlag : uint8_t {
 	AllowZoomMin2x32bpp, ///< Allow use of sprite min zoom setting at 2x in 32bpp mode.
 };
 
+/** Bitset of \c SpriteCacheCtrlFlag elements. */
 using SpriteCacheCtrlFlags = EnumBitSet<SpriteCacheCtrlFlag, uint8_t>;
 
 #endif /* SPRITECACHE_TYPE_H */
diff --git a/src/spriteloader/spriteloader.hpp b/src/spriteloader/spriteloader.hpp
index 4034064cfe..504b76df68 100644
--- a/src/spriteloader/spriteloader.hpp
+++ b/src/spriteloader/spriteloader.hpp
@@ -25,6 +25,8 @@ enum class SpriteComponent : uint8_t {
 	Palette = 2, ///< Sprite has palette data.
 	End, ///< End marker.
 };
+
+/** Bitset of \c SpriteComponent elements. */
 using SpriteComponents = EnumBitSet<SpriteComponent, uint8_t, SpriteComponent::End>;
 
 /**
diff --git a/src/station_base.h b/src/station_base.h
index fc7c66e1da..f2db5c1483 100644
--- a/src/station_base.h
+++ b/src/station_base.h
@@ -207,6 +207,8 @@ struct GoodsEntry {
 		 */
 		AcceptedBigtick = 5,
 	};
+
+	/** Bitset of \c State elements. */
 	using States = EnumBitSet<State, uint8_t>;
 
 	struct GoodsEntryData {
diff --git a/src/station_type.h b/src/station_type.h
index 0c0db0f561..59757a96f3 100644
--- a/src/station_type.h
+++ b/src/station_type.h
@@ -55,6 +55,8 @@ enum class StationFacility : uint8_t {
 	Dock      = 4, ///< Station with a dock
 	Waypoint  = 7, ///< Station is a waypoint
 };
+
+/** Bitset of \c StationFacility elements. */
 using StationFacilities = EnumBitSet<StationFacility, uint8_t>;
 
 /** Fake 'facility' to allow toggling display of recently-removed station signs. */
@@ -83,6 +85,8 @@ enum class StationRandomTrigger : uint8_t {
 	VehicleLoads, ///< Trigger platform when train loads/unloads.
 	PathReservation, ///< Trigger platform when train reserves path.
 };
+
+/** Bitset of \c StationRandomTrigger elements. */
 using StationRandomTriggers = EnumBitSet<StationRandomTrigger, uint8_t>;
 
 /** Animation triggers for stations and roadstops. */
@@ -98,6 +102,8 @@ enum class StationAnimationTrigger : uint8_t {
 	PathReservation, ///< Trigger platform when train reserves path.
 	End, ///< End marker.
 };
+
+/** Bitset of \c StationAnimationTrigger elements. */
 using StationAnimationTriggers = EnumBitSet<StationAnimationTrigger, uint16_t>;
 
 /** Animation triggers for airport tiles */
@@ -109,6 +115,8 @@ enum class AirportAnimationTrigger : uint8_t {
 	AcceptanceTick, ///< Triggered every 250 ticks (for all tiles at the same time).
 	AirplaneTouchdown, ///< Triggered when an airplane (not a helicopter) touches down at the airport (for single tile).
 };
+
+/** Bitset of \c AirportAnimationTrigger elements. */
 using AirportAnimationTriggers = EnumBitSet<AirportAnimationTrigger, uint8_t>;
 
 /* The different catchment area sizes. */
diff --git a/src/string_type.h b/src/string_type.h
index 4aead7c571..61cd76abbf 100644
--- a/src/string_type.h
+++ b/src/string_type.h
@@ -53,6 +53,7 @@ enum class StringValidationSetting : uint8_t {
 	ReplaceTabCrNlWithSpace,
 };
 
+/** Bitset of \c StringValidationSetting elements. */
 using StringValidationSettings = EnumBitSet<StringValidationSetting, uint8_t>;
 
 
diff --git a/src/subsidy_type.h b/src/subsidy_type.h
index d31d7bc6f1..10b49e4359 100644
--- a/src/subsidy_type.h
+++ b/src/subsidy_type.h
@@ -19,6 +19,7 @@ enum class PartOfSubsidy : uint8_t {
 	Destination, ///< town/industry is destination of subsidised path
 };
 
+/** Bitset of \c PartOfSubsidy elements. */
 using PartsOfSubsidy = EnumBitSet<PartOfSubsidy, uint8_t>;
 
 using SubsidyID = PoolID<uint16_t, struct SubsidyIDTag, 256, 0xFFFF>; ///< ID of a subsidy
diff --git a/src/table/strgen_tables.h b/src/table/strgen_tables.h
index 98d1e7b1f7..dfb6c9c1f0 100644
--- a/src/table/strgen_tables.h
+++ b/src/table/strgen_tables.h
@@ -15,6 +15,8 @@ enum class CmdFlag : uint8_t {
 	Case, ///< These commands support cases
 	Gender, ///< These commands support genders
 };
+
+/** Bitset of \c CmdFlag elements. */
 using CmdFlags = EnumBitSet<CmdFlag, uint8_t>;
 
 class StringBuilder;
diff --git a/src/table/townname.h b/src/table/townname.h
index 91854c3d8a..c1a259b3e0 100644
--- a/src/table/townname.h
+++ b/src/table/townname.h
@@ -1735,6 +1735,7 @@ enum class CzechAllowFlag : uint8_t {
 	Long,
 };
 
+/** Bitset of \c CzechAllowFlag elements. */
 using CzechAllowFlags = EnumBitSet<CzechAllowFlag, uint8_t>;
 
 static constexpr CzechAllowFlags CZA_ALL = {CzechAllowFlag::Short, CzechAllowFlag::Middle, CzechAllowFlag::Long};
@@ -1746,6 +1747,7 @@ enum class CzechChooseFlag : uint8_t {
 	NoPostfix, ///< Matched if no postfix was inserted.
 };
 
+/** Bitset of \c CzechChooseFlag elements. */
 using CzechChooseFlags = EnumBitSet<CzechChooseFlag, uint8_t>;
 
 static constexpr CzechChooseFlags CZC_ANY = {CzechChooseFlag::Colour, CzechChooseFlag::Postfix, CzechChooseFlag::NoPostfix};
diff --git a/src/textbuf_gui.h b/src/textbuf_gui.h
index daa79e6d38..2a917c1ca0 100644
--- a/src/textbuf_gui.h
+++ b/src/textbuf_gui.h
@@ -22,6 +22,7 @@ enum class QueryStringFlag : uint8_t {
 	EnableMove, ///< enable the 'Move' button
 };
 
+/** Bitset of \c QueryStringFlag elements. */
 using QueryStringFlags = EnumBitSet<QueryStringFlag, uint8_t>;
 
 /** Callback procedure for the ShowQuery method. */
diff --git a/src/tile_cmd.h b/src/tile_cmd.h
index ff8aea8710..792cdeb2eb 100644
--- a/src/tile_cmd.h
+++ b/src/tile_cmd.h
@@ -27,6 +27,7 @@ enum class VehicleEnterTileState : uint8_t {
 	CannotEnter, ///< The vehicle cannot enter the tile
 };
 
+/** Bitset of \c VehicleEnterTileState elements. */
 using VehicleEnterTileStates = EnumBitSet<VehicleEnterTileState, uint8_t>;
 
 /** Tile information, used while rendering the tile */
diff --git a/src/town.h b/src/town.h
index af7ec690ef..83762c6f9e 100644
--- a/src/town.h
+++ b/src/town.h
@@ -45,6 +45,7 @@ enum class TownFlag : uint8_t {
 	CustomGrowth = 3, ///< Growth rate is controlled by GS.
 };
 
+/** Bitset of \c TownFlag elements. */
 using TownFlags = EnumBitSet<TownFlag, uint8_t>;
 
 /** Data structure with cached data of towns. */
@@ -304,6 +305,8 @@ enum class TownAction : uint8_t {
 	Bribe, ///< Try to bribe the council.
 	End, ///< End marker.
 };
+
+/** Bitset of \c TownAction elements. */
 using TownActions = EnumBitSet<TownAction, uint8_t>;
 
 DECLARE_INCREMENT_DECREMENT_OPERATORS(TownAction);
diff --git a/src/town_type.h b/src/town_type.h
index d23d9910de..375af057ab 100644
--- a/src/town_type.h
+++ b/src/town_type.h
@@ -100,6 +100,7 @@ enum class TownExpandMode : uint8_t {
 	Roads, ///< Allow town to place roads.
 };
 
+/** Bitset of \c TownExpandMode elements. */
 using TownExpandModes = EnumBitSet<TownExpandMode, uint8_t>;
 
 /** Town founding setting values. It needs to be 8bits, because we save and load it as such */
diff --git a/src/vehicle_base.h b/src/vehicle_base.h
index 07452f0ef9..4d4f8173e3 100644
--- a/src/vehicle_base.h
+++ b/src/vehicle_base.h
@@ -39,6 +39,8 @@ enum class VehState : uint8_t {
 	AircraftBroken = 6, ///< Aircraft is broken down.
 	Crashed        = 7, ///< Vehicle is crashed.
 };
+
+/** Bitset of \c VehState elements. */
 using VehStates = EnumBitSet<VehState, uint8_t>;
 
 /** Bit numbers used to indicate which of the #NewGRFCache values are valid. */
diff --git a/src/vehicle_type.h b/src/vehicle_type.h
index a1f4c15ed7..f70896a2ae 100644
--- a/src/vehicle_type.h
+++ b/src/vehicle_type.h
@@ -57,6 +57,8 @@ enum class DepotCommandFlag : uint8_t {
 	MassSend, ///< Tells that it's a mass send to depot command (type in VLW flag)
 	DontCancel, ///< Don't cancel current goto depot command if any
 };
+
+/** Bitset of \c DepotCommandFlag elements. */
 using DepotCommandFlags = EnumBitSet<DepotCommandFlag, uint8_t>;
 
 static const uint MAX_LENGTH_VEHICLE_NAME_CHARS = 32; ///< The maximum length of a vehicle name in characters including '\0'
@@ -88,6 +90,8 @@ enum class VehicleRandomTrigger : uint8_t {
 	AnyNewCargo, ///< All vehicles in consist: Any vehicle in the consist received new cargo.
 	Callback32, ///< All vehicles in consist: 32 day callback requested rerandomisation
 };
+
+/** Bitset of \c VehicleRandomTrigger elements. */
 using VehicleRandomTriggers = EnumBitSet<VehicleRandomTrigger, uint8_t>;
 
 /**
diff --git a/src/viewport_type.h b/src/viewport_type.h
index 017cf77a5a..9bb122b39a 100644
--- a/src/viewport_type.h
+++ b/src/viewport_type.h
@@ -23,6 +23,8 @@ enum class ViewportStringFlag : uint8_t {
 	TransparentRect, ///< Draw a transparent rect around the sign.
 	TextColour, ///< Draw text in colour.
 };
+
+/** Bitset of \c ViewportStringFlag elements. */
 using ViewportStringFlags = EnumBitSet<ViewportStringFlag, uint8_t>;
 
 /**
diff --git a/src/widget_type.h b/src/widget_type.h
index 5c71b1dfb1..846f489f2d 100644
--- a/src/widget_type.h
+++ b/src/widget_type.h
@@ -120,6 +120,8 @@ enum class AspectFlag : uint8_t {
 	ResizeX, ///< Resize horizontally to reach desired aspect ratio.
 	ResizeY, ///< Resize vertically to reach desired aspect ratio.
 };
+
+/** Bitset of \c AspectFlag elements. */
 using AspectFlags = EnumBitSet<AspectFlag, uint8_t>;
 
 /* Forward declarations. */
@@ -375,6 +377,8 @@ enum class NWidgetDisplayFlag : uint8_t {
 	Highlight, ///< Highlight of widget is on.
 	DropdownClosed, ///< Dropdown menu of the dropdown widget has closed.
 };
+
+/** Bitset of \c NWidgetDisplayFlag elements. */
 using NWidgetDisplayFlags = EnumBitSet<NWidgetDisplayFlag, uint16_t>;
 
 /** Container with the data associated to a single widget. */
@@ -570,6 +574,8 @@ enum class NWidContainerFlag : uint8_t {
 	EqualSize, ///< Containers should keep all their (resizing) children equally large.
 	BigFirst, ///< Allocate space to biggest resize first.
 };
+
+/** Bitset of \c NWidContainerFlag elements. */
 using NWidContainerFlags = EnumBitSet<NWidContainerFlag, uint8_t>;
 
 /** Container with pre/inter/post child space. */
diff --git a/src/window_gui.h b/src/window_gui.h
index 2a6bfc889a..048491c980 100644
--- a/src/window_gui.h
+++ b/src/window_gui.h
@@ -27,6 +27,8 @@ enum class FrameFlag : uint8_t {
 	Lowered, ///< If set the frame is lowered and the background colour brighter (ie. buttons when pressed)
 	Darkened, ///< If set the background is darker, allows for lowered frames with normal background colour when used with FrameFlag::Lowered (ie. dropdown boxes)
 };
+
+/** Bitset of \c FrameFlag elements. */
 using FrameFlags = EnumBitSet<FrameFlag, uint8_t>;
 
 class WidgetDimensions {
@@ -155,6 +157,8 @@ enum class WindowDefaultFlag : uint8_t {
 	NoFocus, ///< This window won't get focus/make any other window lose focus when click
 	NoClose, ///< This window can't be interactively closed
 };
+
+/** Bitset of \c WindowDefaultFlag elements. */
 using WindowDefaultFlags = EnumBitSet<WindowDefaultFlag, uint8_t>;
 
 Point GetToolbarAlignedWindowPosition(int window_width);
@@ -236,6 +240,8 @@ enum class WindowFlag : uint8_t {
 	Highlighted,      ///< Window has a widget that has a highlight.
 	Centred,          ///< Window is centered and shall stay centered after ReInit.
 };
+
+/** Bitset of \c WindowFlag elements. */
 using WindowFlags = EnumBitSet<WindowFlag, uint16_t>;
 
 static const int TIMEOUT_DURATION = 7; ///< The initial timeout value for WindowFlag::Timeout.
diff --git a/src/zoom_type.h b/src/zoom_type.h
index 3d07ff3b3b..007191fb72 100644
--- a/src/zoom_type.h
+++ b/src/zoom_type.h
@@ -46,6 +46,8 @@ enum class ZoomLevel : int8_t {
 };
 DECLARE_INCREMENT_DECREMENT_OPERATORS(ZoomLevel)
 DECLARE_ENUM_AS_SEQUENTIAL(ZoomLevel)
+
+/** Bitset of \c ZoomLevel elements. */
 using ZoomLevels = EnumBitSet<ZoomLevel, uint8_t>;
 
 static const uint ZOOM_BASE_SHIFT = to_underlying(ZoomLevel::Normal);