RAR archive of 10.7 MB whose name, ax1, gives no indication of the device, board number or document type it contains. Treat it as an unidentified repair bundle that may hold a schematic, boardview or firmware dump. Open it with WinRAR or 7-Zip and inspect the files inside before use, then compare any board number found in the documents with the one silkscreened on the PCB. If it turns out to contain a BIOS image, confirm it matches the flash chip capacity and back up the original chip before writing anything.
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 @hrtechno. 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.