The RAR is used to test the nature of Dark Matter. Standard Cold Dark Matter (CDM) models sometimes struggle to reproduce the extreme tightness of this relation without additional complex "baryonic feedback".
To use these, the .rar must be extracted into the game's mods folder, and then enabled within the game's menu. 2. Astrophysics: Dark Matter (DM) and RAR DM.rar
These files typically include .dm (data module) files and accompanying graphics/spriters. The RAR is used to test the nature of Dark Matter