Small RAR archive of about 99 KB named M78-PVT, with no brand or board number given. PVT normally stands for production validation test, a late pre-production build stage, so the document likely reflects a near-final board design. The tiny size suggests a boardview or compact file rather than a full schematic set. Inspect it after extraction to confirm which device it belongs to, and match the board number on the PCB before using it to locate components, trace signals or find test points.
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 @generalschematics. 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.