RAR archive of 152 KB for the P4HCJ board, revision 2.0. No brand or document type appears in the name, and the small size points to a boardview or a compact file rather than a large schematic set. Unpack it with a RAR-capable tool and confirm what it contains. Before trusting part locations or net names, make sure P4HCJ and revision 2.0 match the board markings. Files like this help a technician find components, follow nets and probe test points when a board will not start.
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 @ITHINKHS. 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.