MSI MS-8978 revision 0A material compressed into a 425 KB RAR archive. Apart from the board number and revision, the name offers no information on the contents. Its small size suggests a limited set of documents, so verify what is included after extraction. Check the revision printed on the board before working with it. Such files help a technician measure voltages at test points, follow nets between components and work out the power path when diagnosing a board that does not start.
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.