Part number 2SC3805 is the only information in this 184 KB PDF name, and although it is listed as a schematic, the 2SC prefix under Japanese JIS numbering identifies an NPN bipolar transistor. The document is therefore probably a datasheet. It opens in any PDF reader. A repair technician would consult it for absolute maximum ratings, gain and pinout, which matter when hunting a shorted output stage or picking an equivalent. Short-marked SMD parts may carry abbreviated codes, so verify the package before trusting a 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.