Indexed under schematics, this 223 KB PDF takes its name from the JIS part number 2SC2960, an NPN bipolar transistor designation. It is therefore probably a manufacturer datasheet, though the name does not reveal the maker or edition. A repair technician consults such a sheet for the base, collector and emitter pinout, voltage and current ceilings and switching or frequency data. Use it to judge whether an available equivalent is suitable, and double check the pin order, since otherwise identical transistors from different makers may differ.
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.