Undescribed RAR archive of 1.77 MB tagged 4MXS-RH-02, a short code that probably refers to a board with revision RH-02, though the name gives no brand or file type. It belongs to the same family of codes as the 4MXSP and 4MXSV archives but is a different variant, so the contents should not be swapped between them. Unpack it to identify whether it contains firmware or service documents. Match the code against the PCB markings, and back up any flash chip before reprogramming it.
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 @schematicslaptop. 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.