Just announced today, Canon RF 10-20 mm f/4 L IS STM.

MTF charts appear sharper than the already stellar and very well regarded EF 11-24. Comparing the two: Half the weight; smaller (about the size of the RF 14-35) and image stabilizer. Still doesn't accept front filters (rear filter), but first glance, this appears to be a great lens. One that may even end up in my bag.