A 115 KB PDF filed under schematics and named for the 2KBB series, which looks like a component family designation rather than a motherboard or device model. The name states no board number, revision or brand. Files of this size covering a series typically list electrical ratings, pin assignments and package drawings for each variant. A technician would use it to verify a substitute part or to confirm which leg is which before testing it with a meter. Match the full part marking before relying on any values.
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.