Listed among schematics, this 97.3 KB PDF is named for the 2SK1887. Japanese JIS designations starting 2SK belong to N-channel field-effect transistors, so expect datasheet material describing pinout, ratings and characteristics. A technician uses it to orient the part correctly when testing or soldering and to pick a replacement with equal or better voltage and current capability. The name offers nothing more than the part number, so check the device's printed code against the document.
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.