From the Canon press release: "Long gone are the days of optical corrections ..."
Apparently, software correction has replaced optical correction as (strong) barrel distortion correction is forced by the camera and DPP software when using this lens.
Here are some comparisons:
Note that an extreme corner crop has been added to the image quality tool. A small number of lens test results have this crop available (the Canon RF 14-35mm F4 L IS USM Lens and Sigma 150-600mm f/5-6.3 DG DN OS Sports Lens have it), I expect all future test result sets to include it, and if I get time, I'll process this crop for some earlier tests.