ZEISS offers this EF Support Bracket w/ Screws as a spare part for an EF lens mount to attach ZEISS lenses to Canon cameras.
Canon-style EF lens mounts come with a support bracket on their adapter ring, which sits between the mount itself and the ZEISS lens. This is a replacement bracket for EF mounts. The bracket's 1/4"-20 threaded hole accepts a lens support, if necessary.