Archive covering the Sony MBX-189 board with M760 as the project code and revision 1.0 noted, plus a trailing _2 suggesting a second copy or edition. At 4.13 MB it is noticeably larger than the other Sony packages and may bundle more than one document, such as a schematic plus extra files; check the contents after extraction. Technicians use this kind of material to trace rails, locate components and check power sequencing. Confirm the MBX number and revision on the PCB before trusting 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.