Datasheet for the BUW84 and BUW85 NPN power transistors, as stated in the name, in a 101 KB PDF indexed as a schematic. It likely duplicates other copies of the same sheet in the catalogue. Expect maximum voltages, collector current, DC gain, saturation and switching characteristics, along with the package outline. Technicians working on older SMPS and high-voltage stages use it to identify pins and choose substitutes. Verify which of the two parts is on the board, since they share a sheet but carry different voltage limits.
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.