HP EliteBook 640 G9 archive for motherboard DA0X8SMB8H2. The DA0 prefix follows Quanta's numbering, so Quanta is the ODM that built the board for HP. The name does not list what is inside, and at 37.2 MB the package may combine several files; verify after extraction. Schematic or boardview data like this is used to trace power rails, locate test points and diagnose shorts. Check the board number and revision printed on the PCB match before relying on it.
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 @ShareMan_Electronic_Files. 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.