Part number 1SS379 is the only detail in this file name, and the 70.0 KB PDF is most likely the specification sheet for that diode rather than a full device schematic. The JIS prefix 1SS denotes a small-signal silicon diode. Repair work uses such sheets to confirm which pad is anode and which is cathode, to read the marking code, and to compare forward and reverse ratings when choosing an equivalent. Open it with any PDF viewer and confirm the package type matches the part on the PCB.
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.