b2Profile and b2Counters structs are under ! @cond guard

[dpwiz]

box2d/include/box2d/types.h

Lines 508 to 560 in 56edae7

	//! @cond
	/// Profiling data. Times are in milliseconds.
	typedef struct b2Profile
	{
	float step;
	float pairs;
	float collide;
	float solve;
	float solverSetup;
	float constraints;
	float prepareConstraints;
	float integrateVelocities;
	float warmStart;
	float solveImpulses;
	float integratePositions;
	float relaxImpulses;
	float applyRestitution;
	float storeImpulses;
	float splitIslands;
	float transforms;
	float sensorHits;
	float jointEvents;
	float hitEvents;
	float refit;
	float bullets;
	float sleepIslands;
	float sensors;
	} b2Profile;
	/// Counters that give details of the simulation size.
	typedef struct b2Counters
	{
	int64_t byteCount;
	int bodyCount;
	int shapeCount;
	int contactCount;
	int jointCount;
	int islandCount;
	int stackUsed;
	int staticTreeHeight;
	int treeHeight;
	int taskCount;
	int colorCounts[24];
	// Number of contacts touched by the collide pass (graph contacts + awake-set non-touching).
	int awakeContactCount;
	// Number of contacts recycled in the most recent step.
	int recycledContactCount;
	} b2Counters;
	//! @endcond

The types are used in the samples and their producers are part of the API:

/// Get the current world performance profile
B2_API b2Profile b2World_GetProfile( b2WorldId worldId );

But doxygen doesn't export those and they don't end up in the api_dump.py JSON export.