Sony MS10 board documentation for MBX-149, marked MP, a mass-production release. The name also lists 955 and 945GM/PM, which points to Intel 945GM and 945PM chipset variants, so the drawings may cover both integrated and discrete graphics builds. The 1.69 MB RAR likely contains schematic pages. Use them to trace rails, check chipset power and locate parts around faults. Make sure your MBX-149 board matches the variant shown, as integrated and discrete versions differ in populated parts.
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.