(A gaming forum, a tech support page, or a download site?) Once I know, I can find the specific story behind the file! VR DD Class Type 1 Pack - ZecRail
A support article describes downloading and unzipping a DPInsts.rar file to install CH340 drivers for the xTool D Series laser machine . D Series 4.rar
A Repeater-Builder article mentions legacy programming software for ALF, EPH, and DPH series radios that originally came in "RAR" files. This content would interest those looking to "downband" or repurpose older high-band portables. (A gaming forum, a tech support page, or a download site