Here is a new Canon patent application, as usual for RF-mount lenses. Canon patent application…
Canon patent for EF 12-20mm f/4 lens for full-frame DSLR
Canon patent for another ultra wide angle zoom lens? Appears so, the patent describes an EF 12-20mm f/4 lens for full-frame DSLRs. Maybe not a “L” lens. You can read the patent literature here.