RAR archive of 1008 KB covering the Sony VAIO models PCG-71811V and PCG-71912V, both linked in the name to the MBX-247 mainboard. Sharing one board across PCG model codes is common for VAIO lines, so the same documentation may serve both units. MBX-247 is known as a Quanta-built board, which helps when cross-referencing other material. The contents are probably schematics for tracing rails and signals. Verify the MBX number and PCB revision on your board, since several revisions of this platform exist.
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 @IT_SERVICE_WORLD. 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.