A 51.5 KB PDF named for the 2SC1573 with an _E suffix, categorised as a schematic. Since 2SC is the JIS prefix for NPN bipolar transistors, this is best read as a short component datasheet giving lead order, maximum voltages and currents, dissipation and gain information. It is opened with any PDF reader during repair work to confirm pins before probing or replacing the part. The name names no manufacturer or package, so compare the outline drawing with the transistor actually mounted on 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.