A 41.5 KB PDF for the 2SB970 transistor, with an _E suffix the file name leaves unexplained. Under the Japanese JIS numbering system the 2SB prefix identifies a PNP bipolar transistor aimed at low-frequency use, such as audio stages, drivers or power switching. Although catalogued as a schematic, a document this small is most likely a component data sheet. Technicians use it to check pin assignment, package style, collector ratings and gain before choosing a substitute part. Any PDF reader will open it.
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.