At 108 KB, this PDF is labelled with the transistor type 2SC4221 and nothing else, so no board, model or revision is identified. The 2SC prefix is the Japanese JEITA marking for an NPN bipolar transistor, which means the document is almost certainly a component datasheet. Expect maximum ratings, hFE classification, switching or frequency data and a package outline. Read the pin diagram carefully, since lead order differs between packages and getting it wrong while probing or replacing a part is a common mistake.
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.