The 2SK2843 is the only detail in this file name, an N-channel FET designation under the Japanese JIS scheme. Although indexed as a schematic, the 411 KB PDF is most likely the device datasheet. A technician would open it to check pinout and package outline, look up absolute maximum ratings, and decide whether an alternative MOSFET is electrically compatible. Before swapping parts, confirm the marking on the original component and test the surrounding circuit for the fault that destroyed it.
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.