Quanta D91B motherboard documentation, revision 1A, in a 1.28 MB RAR archive. The name does not identify the device or list the files inside, which are likely a schematic and possibly boardview data. D91B appears to be a variant within Quanta's D91 project, so confirm the exact letter on your PCB, as A and B versions may differ. Technicians use such drawings to check power rails, follow charging and USB circuitry and locate components behind a short. Verify revision 1A on the board before comparing 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 @IT_SERVICE_WORLD. 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.