Datasheet PDF of 204 KB for the 2N3771, a JEDEC 2N-series transistor, catalogued in the schematic section. The RE ending in the name is not explained; it may be a revised or re-edited manufacturer copy. Use it to look up maximum ratings, gain figures, safe operating area and the mechanical outline before replacing a damaged part in an amplifier or power supply stage. Open it with any PDF viewer, and check that the marking and case of the original component match what the sheet describes.
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.