ESP is a expansion file used by such games as Fallout 3 and Fallout: New Vegas. ESP plugin files can be used to make changes to the game’s code. Usrs can modify such aspects of the game as environments, add new assets, or change some game preferences.

ESP file can store aditional game world objects or localization data. Users can alter AI settings of characters or interactions with game’s environments. ESP files must be installed along with ESM files.