Lowercase-named PDF for the 2SB1474 transistor, about 54 KB, stored in the schematic category but most likely a manufacturer datasheet. Under Japanese JIS numbering, 2SB marks a PNP device for low-frequency circuits. The name carries nothing beyond the part code. Use it to look up the pinout, package outline and absolute maximum ratings, which matters when diagnosing a shorted transistor or selecting a substitute; confirm that the component on the board really carries this number before ordering.
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.