The name identifies only the part 1SS377, so this 69.8 KB PDF is best treated as a diode data sheet even though it is indexed as a schematic. In JIS numbering, 1SS covers small-signal silicon diodes used in switching, clamping and protection roles. On the bench the sheet helps confirm polarity, package outline and voltage and current limits while checking a suspected shorted diode with a multimeter. Open it in a PDF viewer and compare the marking code with the component on the board.
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.