Catalogued as a schematic, this 143 KB PDF is named 87cnq020 and states no brand or device. The string resembles a power-semiconductor part code of the kind used for Schottky rectifier modules, but the name alone does not prove it, so check the header once opened. Sheets of this type give forward voltage, reverse rating, current capacity, thermal data and package drawings. They help when choosing a substitute part in a power supply or checking whether a failed rectifier was rated correctly for the circuit.
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.