I'm typing this on a computer running Android, which means it doesn't support DHCPv6. I would describe it as supporting a subset of IPv6 functionality.

Well, we'll have to see what all the "in-between" bits do. There's a lot in it, that will require implementation by countless layers of routers, switches, caches, firewalls, etc.

Look at Bluetooth, for an example, or TIFF.

I printed out the Bluetooth spec once, just for Ss and Gs. It was over 2,000 pages (double-sided).

I once tried writing a fully-compliant TIFF reader. Didn't go so well.