Here the name gives only the part number 12CWQ03FN, and at 129 KB the PDF is almost certainly a single component datasheet. It belongs to the same naming family as the other 12CWQ files, consistent with International Rectifier rectifier diode numbering. Technicians use such a document to read maximum reverse voltage and forward current, identify the package and pinout, and pick an equivalent. Open it in any PDF viewer and compare the marking on the board part before replacing 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.