The 2SC3637 is documented in this 117 KB PDF. Following the Japanese JIS scheme, the 2SC prefix denotes an NPN bipolar transistor, and no model, board or revision appears in the name. Content is most probably a component datasheet with ratings, gain classes and an outline drawing. Before replacing the part, compare its pinout with the PCB footprint and make sure any substitute equals or exceeds the listed breakdown voltage, collector current and power dissipation.
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.