source-sdk-2013/sp/game/mod_hl2/scripts/surfaceproperties_manifest.txt

// Override this file in your mod directory so you can load the base HL2 file as well
// as new properties.  
// NOTE: Listing a property twice (e.g. in separate files) means that
// the values in the second definition will override the first definition

// NOTE: Each file must have a unique name.  The physics system does not understand mods and will not
// parse the same file (compared by name) twice.

surfaceproperties_manifest
{
	"file"		"scripts/surfaceproperties.txt"
	
	// List additional surface property files here:
	"file"		"scripts/surfaceproperties_hl2.txt"

	
}