RAR archive for the Sony VAIO motherboard MBX-157, which the name also ties to the RJ6 design with a board code of MB-C and the number 0508, likely a date or revision tag. Contents are not listed, but such packages normally hold the service schematic for the board. Unpack with 7-Zip or WinRAR before use. The material helps with tracing power rails, checking the charging circuit and locating components around a short. Confirm the MBX number on the PCB before relying on any value shown.
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.