Official documentation for SDL configuration variables
This file contains functions to set and get configuration hints, as well as listing each of them alphabetically.
The convention for naming hints is SDL_HINT_X, where "SDL_X" is the environment variable that can be used to override the default.
In general these hints are just that - they may or may not be supported or applicable on any given platform, but they provide a way for an application or user to give the library a hint as to how they would like the library to work.