A 1.75 MB RAR package for the Sony MBX-170 motherboard, with no model, ODM or revision stated in the name. MBX numbers are Sony identifiers for VAIO mainboards built by contract makers, so the files inside likely name the real ODM project code. An archive of this type normally holds a schematic used to trace power rails, check the charging circuit and locate components and test points during repair. Check the board number printed on the PCB and the revision on the title block before relying on it.
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.