Compressed RAR package for the M4A88T-M motherboard, with 2.00G in the name, most likely the board revision. The archive is only 212 KB, which fits a boardview or compact diagnostic file rather than a firmware dump, though the name does not list the contents. A file like this helps a repair technician find components, follow signal paths and measure test points around VRM and chipset areas. Confirm the revision silkscreened on the PCB matches 2.00G, since layouts can change between revisions.
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 @boardview. 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.