Carrying only the code 16SYQ030C, this 48.5 KB PDF is catalogued as a schematic and names no device, board or revision. The pattern matches International Rectifier Schottky rectifier numbering, with the numeric part after the letters usually indicating the voltage grade. The content is therefore likely a datasheet rather than a board diagram. Technicians use it to confirm ratings and lead configuration when replacing a rectifier; check the stamped code on the real component before relying on it.
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.