A 128 KB PDF for the 2SC4564, filed among schematics but almost certainly a datasheet, since the name is just a JIS transistor number. The 2SC prefix denotes an NPN bipolar transistor of the high-frequency class; no further specifics appear. It serves for checking the pin order and case drawing, absolute maximum ratings and gain characteristics, which matters when diagnosing a dead stage or picking an equivalent. Compare the printed code on the board part with the document first.
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.