The part number 2sk2210 is the sole clue to this 33.6 KB PDF, catalogued under schematics but most likely a short component datasheet. Japanese JIS/EIAJ designations with the 2SK prefix denote N-channel FETs; brand and package are not given. A repairer would use it to identify the gate, drain and source leads and read the voltage and current limits. The small file size hints at a condensed document, so confirm important figures elsewhere if they seem incomplete.
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.