PDF for the FQP13N06L MOSFET, with the name noting 13.6 A, 60 V and logic-level gate drive. Filed as a schematic, the 664 KB document is most likely the manufacturer datasheet with ratings, on-resistance at low gate voltages and the TO-220 pin layout. A logic-level part switches fully from microcontroller outputs, so a replacement must also be logic level, not just match voltage and current. Technicians use the sheet to confirm pinout and check gate threshold, and should verify the exact marking on the device 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.