RAR archive of about 3 MB whose name, edit, says nothing about its contents, the device it belongs to or the board it targets. It may hold a modified firmware image, an editing tool or working files, so open it and inspect everything before use. If it contains a BIOS image, check it against the board number printed on the PCB, compare its size with the flash chip capacity, and always keep a backup of the original chip contents made with a programmer before writing anything modified.
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 @generalproblemsolved. 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.