At 287 KB this PDF for the 2SK1875 is larger than its neighbours, which may mean extra graphs or pages, though the name says nothing more than the part number. It sits under schematics, but the 2SK prefix marks an N-channel field-effect transistor in Japanese JIS numbering, so treat it as a datasheet. It helps confirm pinout, ratings and package before testing or replacing the part. Check that the marking on the device matches the document, as the maker is not stated.
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.