Covering the 2SK2733, this 413 KB PDF sits among schematics but is most likely the device datasheet, since 2SK is the Japanese JIS prefix for N-channel field-effect transistors. Its size suggests full content including curves and package drawings. Repairers use it to check absolute maximum ratings, on-resistance and gate threshold, to identify pins before removal, and to evaluate equivalents when sourcing parts. The file name gives only the part number, with no manufacturer or revision, so match the component marking first.
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.