Update: Canon News has dug a bit further and come to the conclusion that these optical formulas are for a fisheye due to the lenses having a 175 degree field of view.
A new patent showing an optical formula for a new wide angle prime has appeared. The full frame lens in the application is an EF 15mm f/4, while the APS-C optical formula of a EF-M 9.5mm f/4 shows a shorter backfocus than an EF-S lens and could actually be EF-M.
Japan Patent Application 2018-004726
Canon EF-M 9.5mm f/4
- Focal distance 9.50
- F number 4.10
- Imaging field angle (degree) 175
- Image height 13.66
- Whole length of the lens 63.97
- BF 23.16
Canon EF 15mm f/4
- Focal distance 15.18
- F number 4.12
- Imaging field angle (degree) 175
- Image height 21.64
- Whole length of the lens 130.16
- BF 58.19