This file is located in the environment folder and allows you to perform automatic presets of autocad variables. It is made up of the SYSTEM and DOCUMENT sections. The first contains the AutoCAD system variables that the user wants to preset. The second section contains the autocad variables related to the document that the user want to set automatically. The system variables are set when the application starts while those related to the document each time you open a file in autocad. As with all prs files, the definition of variables must be written in the name = value form. If the two sections do not contain any entries, there will be no preset.