Archive in RAR format, 1.49 MB, named after board code 5MMS with the RH-01 suffix, likely an early revision marker. Nothing in the name reveals whether the package carries a circuit diagram, a boardview or a BIOS image, so open it with 7-Zip or WinRAR first and check the files. For diagnostics such documents help trace power rails, find test points and locate a shorted component. Match the board code and revision on the PCB to this file before trusting values or part placement.
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 @cyberlanelectonik. 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.