Archive named only after the H81M-C board, roughly 296 KB, with no brand, revision or contents listed. The model points to an Intel H81 chipset desktop motherboard, a name used by ASUS. Because the name says so little, extract the RAR and identify the material inside, whether boardview, schematic or something else, before using it. Several H81M-C revisions exist, so compare the revision silkscreened on the board with the documents before tracing power rails, checking a short or locating components from them.
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.