Datasheet-style PDF, 181 KB, for the JEDEC part 2N6251, filed in the schematic category. Apart from the part number, the name carries only an RE suffix that it does not explain. Documents like this supply the electrical characteristics, safe operating area, thermal data and mechanical outline of a discrete semiconductor. In repair they help verify readings taken in circuit, confirm terminal identification before desoldering, and judge whether a cross-reference part has adequate voltage and current margins.
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.