How to convert .rargb files to .mkv format.
It appears that converting Warez Movies directly to Matroska Videos (.rargb to .mkv conversion), per se, is not possible. But it also might not be necessary. It is very likely that your RARGB video already is in .mkv format, and you just have known file extensions hidden. That can be changed in your folder settings in Windows.
The database currently does not contain any rargb software converter.