At 329 KB this is the largest sheet in the group, a PDF catalogued as a schematic for the 2N6515 with an unexplained RE suffix. The 2N prefix marks a JEDEC-registered discrete semiconductor, so the file is most probably a manufacturer datasheet with characteristic graphs, ratings tables and package drawings. It is useful for confirming pin order, checking safe operating limits and choosing a substitute during board repair. View it in any PDF reader and match the case and marking to the actual 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.