ZIP archive of 1.98 MB with a generic name that gives no device, brand or board number; it is catalogued as schematic material and presumably holds one or more PDF files. Extract it with any archive tool and check the title blocks inside to identify which product and revision the documents cover. Once identified, schematics can be used to trace power rails, find test points and look up component values, provided the board number on the PCB matches the drawings.
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 @phoneSchematics. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.
Built-in OS tools7-Zip