PDF for the IRF3205 MOSFET, with 55 V and 110 A noted in the file name. Although categorised as a schematic, the 97.8 KB file is likely the datasheet presenting low on-resistance figures, gate threshold, switching characteristics and the TO-220 pin order. This part is common in car inverters, motor controllers and low-voltage converters, so the sheet assists in pin identification and choosing equivalents. Keep in mind that the quoted current is often package or silicon limited under ideal cooling, and verify the marking on the actual component.
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.