Sony motherboard MBX-250 documentation in a 1.52 MB RAR, with no model, ODM or revision in the name. The archive most likely contains a schematic for this VAIO board. MBX numbers are Sony's own board identifiers printed on the PCB, while the actual design often comes from an ODM such as Quanta, Foxconn or Wistron. Use the drawings to trace power rails, check signals and find components on a short. Read the revision inside the title block and match it to your board before measuring.
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.