Archive named RC4559, 343 KB, with no brand listed. RC4559 is the part number of a dual operational amplifier, so the contents are most likely the datasheet for that IC rather than a board schematic. A datasheet gives the pinout, supply range, electrical characteristics and typical application circuits, which helps when checking an op-amp in audio or analog sections of a device or choosing a substitute. Extract the archive to confirm, and compare the package type and marking on the board with those in the document.
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.