A 94.9 KB PDF for the 2SC3088, filed as a schematic but in practice probably a component datasheet. Its name contains just the part number. JIS coding uses 2SC for NPN bipolar transistors in the high-frequency group. When diagnosing a shorted or open transistor with a multimeter, the pinout and rating tables in a document like this tell you what readings and limits to expect. Compare the marking on the part, including any gain suffix, before choosing a substitute from other series.
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.