Small 153 KB RAR archive labelled X555 with the number 3.6, possibly a version tag; the name does not state the brand, though X555 is an ASUS model designation. Its compressed size suggests contents such as an embedded controller image or a highly compressible BIOS, but only extraction will show what it holds. Open it with an archiver and check file sizes against the chips on the board. Verify the motherboard revision, and back up any chip before reprogramming it with a hardware programmer.
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 @biosarchive. 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.
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →