PDF document for the 2SK2775, filed under schematics although the part number points to a component datasheet rather than a board drawing. The 2SK prefix follows the Japanese JIS scheme for N-channel field-effect transistors, so expect ratings, pinout and package details instead of circuit sheets. At 40.4 KB it is a short document. Technicians use such a sheet to confirm drain-source voltage, current and on-resistance before choosing a replacement, and to identify gate, drain and source pins when checking for a shorted FET.
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.