The 2SB1302 transistor is documented in this 95.4 KB PDF, which the index files as a schematic. JIS part numbers beginning with 2SB identify PNP devices intended for low-frequency applications. Apart from the part number, the name carries no information. A repair technician would consult it to read the pinout and package drawing, confirm gain and voltage ratings, and verify that any cross-reference substitute matches lead order so the part can be fitted without modifying the board.
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.