RAR archive of 906 KB labelled 558-1-4-01 R21, with no brand or device stated. The numbering looks like a board or document code, and R21 most likely marks a revision, but neither can be confirmed from the name alone. Extract it and identify the contents, which may be a schematic, a boardview or a firmware file. Before using anything inside, compare the code and revision with the markings printed on the PCB you are repairing.
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 @cyberlanelectonik. 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.
7-ZipWinRARThe Unarchiver (macOS)