ZIP archive of 29.3 MB for the ASUS K55DE laptop motherboard, revision 2.0. The name does not state what is packed inside, so it may contain a schematic, boardview data, BIOS or a combination for this model. Repair technicians use such material to trace power rails, follow the startup sequence, and locate components or test points when diagnosing no-power or short faults. Check that the main board revision printed on the PCB reads 2.0, because ASUS revisions of the same model can differ.
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 @azvoltagemap. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.