Largest in size among these, an 7.76 MB RAR archive for MSI board MS-7173. The name says nothing about the contents, which could be a full schematic set, firmware, or several files together; open it with 7-Zip or WinRAR. MSI uses MS-7xxx numbering for its desktop motherboards, and the code is printed on the PCB. Confirm the number and revision before tracing rails or checking shorts from the documents, and back up the original BIOS chip before flashing anything found inside.
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.