The 2N6274 is covered by this 169 KB PDF, indexed as a schematic though it is presumably a manufacturer datasheet for the component. The name adds only an RE tag of unclear meaning, possibly a revision mark. The 2N prefix comes from the JEDEC registration system for semiconductors with two junctions. Technicians open sheets like this in any PDF viewer to look up pinout, package drawing, maximum ratings and test conditions when diagnosing a failed stage or picking an equivalent part.
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.