Part documentation named 5HN02M, a 41 KB PDF indexed under schematics. It refers to a single discrete semiconductor rather than a circuit board, and the M ending is presumably a package variant. Inside you can expect pin assignment, absolute ratings and mechanical data. For board repair it serves to identify a component by its code, interpret meter readings across its pins and pick a compatible replacement. Confirm orientation and footprint on the outline drawing before soldering.
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.