Where are non-Lua functions located?

Where are non-Lua functions located in the Garry’sMod files? By “non-Lua” I mean useable from Lua but not defined in Lua, like most functions usable in gmod (including the ManipulateBone functions, the get/set material, color, and model functions, the isenabled/enable gravity, collisions, and drag functions, etc.).

Those functions are source engine functions, located in the dlls loaded into gmod. Garry binds them to lua.