Compressed RAR package for the ASUS X555LD mainboard, revision 2.0 according to the name. The archive contents are not listed, but packages of this size for ASUS laptops usually hold a schematic PDF and sometimes a boardview file. Extract it with WinRAR or 7-Zip and check what is inside before use. Technicians rely on such material to trace power rails, follow signal paths and find test points while diagnosing no-power or short faults. Confirm that the revision silkscreened on the PCB reads 2.0, because component placement can differ between revisions.
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 @alischematics. 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.