Filed under schematics, this 74.8 KB PDF is named 16cyq100c, a code that resembles International Rectifier or Vishay dual Schottky rectifier numbering. It most likely holds the datasheet for that part, with package pinout, reverse voltage, forward current and thermal data. A technician would use it to confirm a replacement in a power supply secondary stage or to interpret diode-test readings. Compare the full marking on the component body with the document, since suffix letters change package and configuration.
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.