Quanta U83 board files, part number DA0U83MB6E0, revision 1A, stored in an 835 KB RAR archive with no laptop model named. The DA0...MB code is the Quanta format for main boards, and the letter near the end marks the PCB build, so DA0U83MB6E0 should match your silkscreen exactly. A schematic like this lets a technician find power rails, check the always-on circuits, locate test points and track down a shorted component. Extract it with WinRAR or 7-Zip; contents are typically PDF pages readable in any viewer.
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.