The name of this 156 KB PDF is just the part number 2SC4134, so despite its schematic label it should be the datasheet for that transistor. In Japanese JIS numbering 2SC marks an NPN bipolar transistor, and boards typically show the abbreviated code C4134. The sheet is useful for working out pin order before testing junctions, checking ratings against the circuit and picking a cross-reference part. Since neither maker nor gain grade is stated, compare the original marking, suffix and package outline before substituting.
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.