Tiny plain-text file of 116 bytes called link.txt, which most likely holds a web address or a short note rather than repair data. The name gives no model, board or firmware information. Any text editor such as Notepad will open it. It usually accompanies an archive of schematics or dumps and points to a related resource or source. Treat any link inside with caution and check where it leads before opening it. It contains no diagrams, boardview data or flashable firmware.
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 @biosarchive. Enginerys does not host this file.