RAR archive for the Lenovo IdeaCentre C305 all-in-one, marked as the discrete version, which points to the variant with a separate graphics chip rather than integrated video only. The 1.68 MB file names no board number or document type, so inspect the contents to learn whether it is a schematic, a boardview or something else. Documents like this help trace power rails and locate components on an all-in-one mainboard. Make sure your unit is the same discrete-graphics variant and that the board markings match.
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 @alischematics. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.