User:Pinsplash/Dissections of Valve maps/Half-Life 2

See also: Half-Life 2 map reference.

Misc. Findings

 * Many worldspawns contain unused keyvalues similar to ones on light_environment and env_fog_controller. Another mysterious KV is "sounds".
 * Maps have multiple light_environments, with identical values.
 * Many maps have env_sun keyvalues which are left there from a previous implementation of the entity which allowed the mapper to use up to four textures at once, each with their own X and Y sizes.