Catalogued as a schematic, this small PDF of 42.3 KB is in practice a component data document for the 2SB852K, a part numbered under the Japanese JIS scheme where the 2SB prefix marks a PNP transistor intended for low-frequency use. The trailing K is not explained by the name, so treat it as a variant or grade code to confirm in the text. Technicians open such sheets in any PDF reader to check the pinout, package outline and maximum ratings before fitting a substitute on a power or audio stage.
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.