Sony archive for model M931 with the IRX-5300 designation and motherboard MBX-215. Sony VAIO boards use the MBX-xxx numbering, which is printed on the PCB and is the key identifier when choosing documentation. The package is likely a schematic and possibly boardview data, useful for tracing power rails, locating the charger and EC circuitry and checking for short circuits. Note that MBX-215 also appears under related model codes, so check the board revision on your unit against the drawing before relying on component values.
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.