ZIP archive of 158 KB labelled for the ASUS X555LP laptop; the name does not say whether it holds a schematic, boardview or BIOS, so open it to confirm the contents. The small size suggests documentation or a boardview rather than a full firmware image. Such files are used for tracing power rails, locating components or reflashing firmware depending on what is inside. Before using it, compare the motherboard revision printed on the PCB, since ASUS X555 series boards came in several 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 @boardviews. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.