Small 26.3 KB PDF datasheet for the 2N5246 semiconductor device. The name only gives the part number, without manufacturer, package or revision. Inside, expect device type, pinout, maximum ratings and key electrical parameters. A technician uses this sheet to identify the leads correctly, test the part out of circuit, and compare it with available substitutes when the original is obsolete. Open it with any PDF reader, and confirm the case marking on the board part corresponds to this number before relying on it.
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.