A small PDF filed as a schematic and named for the 10ETF10S and 10ETF12S part numbers, two variants sharing one document. The naming pattern matches International Rectifier and Vishay power rectifier codes, where an S suffix usually marks a surface-mount package, so expect a component datasheet rather than a board drawing. Technicians use such sheets to confirm pinout, voltage and current ratings and package marking when replacing a failed diode. Compare the marking on the part with the document before ordering a substitute.
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.