Named only 1SS366, this 50.5 KB PDF is catalogued as a schematic yet points to a single semiconductor: in JIS designations 1SS stands for a small-signal silicon diode. Expect absolute maximum ratings, electrical characteristics and a package outline rather than a circuit diagram of a device. It helps when a diode in a logic or protection circuit is suspected and a replacement must be chosen. Any PDF viewer opens it; verify the marking code and package of the fitted part match.
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.