The 2SB1674 named here is, under JIS conventions, a PNP bipolar transistor; this 52.6 KB PDF, despite its schematic category, is therefore most likely the datasheet. A datasheet of this sort covers absolute maximum ratings, characteristic tables, gain groups and package dimensions with lead identification. In repair work it is consulted to verify that a measured part behaves as specified, to orient the device correctly on the board, and to confirm whether a cross-reference type is an acceptable electrical and mechanical substitute.
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.