RAR archive, 170 KB, for the P8B75-V labelled 2.00, which most likely refers to board revision 2.00. The file name does not reveal what the archive holds, so open it and check whether it contains a boardview, schematic or other service data. If it is layout data, viewers such as OpenBoardView or FlexBV will open it for locating components and following nets. Other revisions of this board are also listed, so match the number printed on the PCB to avoid probing the wrong spots.
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 @schematicslaptop. 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.