Catalogued as a schematic, this 200 KB PDF is named 20CJQ030 and says nothing about a device, board or revision. The string resembles an International Rectifier Schottky rectifier part number, so the content is likely a datasheet rather than a circuit of a full board. Any PDF reader opens it. It is useful for reading reverse voltage and current ratings, the package outline and lead assignment when replacing a shorted diode; check the marking on the part itself before trusting the match.
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 .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.