Quanta TWK motherboard documentation, revision 1A, delivered as a 1.48 MB RAR archive; the file name does not identify the brand, model or board part number. The package most likely contains the schematic, useful for following power sequencing, measuring rails at test points and tracking down shorts or missing voltages. Quanta is a Taiwanese ODM that supplies boards to several brands, so the code on the PCB silkscreen is the reliable identifier. Extract it with WinRAR or 7-Zip and compare TWK rev 1A with your board first.
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.