Very small PDF of 26.3 KB named with the part number 2N5639 and nothing else. Listed as a schematic, it is most plausibly a short datasheet, since 2N codes are JEDEC designations for discrete semiconductors. The compact size suggests only a page or two of key parameters and a pin diagram. Use it to confirm lead order and limits when replacing or testing the part with a meter. No board, brand or revision is stated, so check the marking on the actual component first.
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.