RAR archive labelled for the M4A88TD-M micro-ATX motherboard, size 235 KB. The file name gives only the model, with no revision, document type or version, so the exact contents must be checked after extraction. Its small size suggests boardview or schematic data used for locating components and test points, following power sequencing and narrowing down shorts. Many boardview formats open in tools such as OpenBoardView or FlexBV. Always compare the revision marked on the PCB with the documentation, as part positions may differ 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.