Archive of 5.55 MB for the Sony MBX-267 motherboard. MBX is Sony's main-board designation, and the board number is printed on the PCB along with a revision, which the name here does not state, so check it against the contents. The file type inside is not given, but the size points to a schematic set. Typical use is following power rails from the DC jack, checking the charger and voltage regulators, and locating components or test points while isolating a short circuit.
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 @ITHINKHS. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.
Built-in OS tools7-Zip