The name points to the 2SB1219 transistor, and this 43.6 KB PDF with an _E suffix, though filed as a schematic, should be its datasheet. Under JIS conventions, 2SB parts are PNP transistors for low-frequency circuits. The document typically provides the outline and pin layout, absolute maximum ratings, gain ranges and characteristic graphs. A technician uses these to test the device out of circuit and to confirm a substitute can handle the same voltage and current. Match the marking before replacement.
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.