Demystifying Dolby Vision - Profile Levels, Dolby Vision levels, MEL & FEL

This was very helpful, but I’m looking for info on Profile 8.4 and don’t see it listed. Dolby’s own site is full of marketing fluff and short on specifics.

I understand that 8.4 uses HLG rather than PQ, and also that the iPhone 12 Pro shoots video in Profile 8.4.