MSI board documentation in a 1.77 MB RAR, identified only by board number MS-B9091 and revision 1.0; no product name appears in the file name. MSI uses its MS-prefixed codes across desktop, notebook and industrial products, so matching the exact code printed on the PCB is the reliable way to confirm fit. The archive probably contains schematic pages that help trace power rails, find the source of a short and identify parts around connectors. Extract it and compare the revision in the title block with the board before use.
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 @IT_SERVICE_WORLD. 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.