Filed as a schematic, this 134 KB PDF is named for the 9AF40 and 9AF60 parts, two variants in one document. The name looks like a semiconductor part number, so the content is most likely a component datasheet with ratings, pinout and package data rather than a board drawing. Technicians use such documents to identify a failed device, confirm its limits and select a compatible replacement. Because the name gives no further detail, check the marking on the physical part against the sheet before relying on 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.