Compact 16.0 KB PDF datasheet for the 2N3055 from UTC, as indicated in the name, filed in the schematic category. It covers that manufacturer's version of this 2N-series transistor, typically with ratings, characteristics and package outline. Repair technicians use it to verify pinout and limits before substituting a UTC part for another brand. Opens in any PDF reader. Different makers may publish slightly different figures and package options, so check the marking on the fitted component first.
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.