Compressed package for Sony VAIO motherboard MBX-152, labelled with design code MS32, 2.58 MB in RAR form. The file list is not stated, though archives like this usually contain the board schematic as a PDF. Extract it with a standard archiver and check the contents. Repair use typically involves following voltage rails, verifying power sequencing signals and finding which components connect to a shorted net. Sony prints the MBX designation on the board itself, so match it before taking measurements against the drawings.
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 @alischematics. 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.