CLIENT_COMMAND("playmusic \"%s\" \"%s\"\n", g_SoundTracks[cdtrack], g_SoundTracks[cdtrack2]);

backend/sys/const.h -  S_WARN, S_ERROR, TRUE, FALSE, NULL(=nullptr) etc

// все Shot-команды
player.shot CBasePlayer::ClientCommand

// print messages at various developer level
IMPORT void Con_Printf( string fmt, ... );  // player mode
IMPORT void Con_DPrintf( string fmt, ... );  // developer mode
IMPORT void Con_Reportf( string fmt, ... );  // debug mode
IMPORT void Exception( const string fmt, ... );  // debug mode      // UNDONE
IMPORT void FilePrintf( string *file, string fmt, ... );

#define printf  Con_Printf
#define Msg  Con_Printf

Con_DPrintf(S_WARN "%s will get damage %i\n", pEnt->m_classname, damage);
Msg(S_WARN "UTIL_FindEntitiesInSphere found %i matches\n", result.count());

public/dbgdraw_api.h

NDebugOverlay
	// draw methods
	void Line( const vec3 &p0, const vec3 &p1, const vec3 &color = 1.0f, kDepthMode depthMode = kDepthTestEnable );
	void Circle( const vec3 &center, const vec3 &direction, float radius, const vec3 &color = 1.0f, kDepthMode depthMode = kDepthTestEnable );
	void Arrow( const vec3 &p0, const vec3 &p1, float size, const vec3 &color = 1.0f, kDepthMode depthMode = kDepthTestEnable );
	void Box( const xform &transform, const bbox &bounds, const vec3 &color = 1.0f, kDepthMode depthMode = kDepthTestEnable );
	void Sphere( const vec3 &center, float radius, const vec3 &color = 1.0f, kDepthMode depthMode = kDepthTestEnable );
	void AABB( const bbox &bounds, const vec3 &color = 1.0f, kDepthMode depthMode = kDepthTestEnable );
	void Axis( const xform &transform, float size, kDepthMode depthMode = kDepthTestEnable );

#include <dbgdraw_api.h>
NDebugOverlay::Sphere(origin, 10.f);