H81M-PLUS motherboard package as a 515 KB RAR, for a micro-ATX board on the Intel H81 platform. Its name gives no revision and no indication of the content type, so open it to see what is included, likely boardview or schematic data. Such files help with locating components by designator, following nets across both PCB layers and identifying test points for voltage and resistance checks during no-power diagnosis. Make sure the revision silkscreened on the board corresponds to the documentation before trusting the layout.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @boardview. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.