Do folk see where I'm going with this?
Where in the standards does it say that a packet with any of these headers should/may/must not be used on the Internet?
I don't understand the reasoning at all. My opinion is that yes, we perhaps should not create packet generators that send line-rate with small packets with these headers "because we can", but I see little reason not to generally create a test that perhaps does a few pps (or less) of sending these packets (all combinations of headers) to test what happens.
There is nothing on the Internet today stopping anyone with IPv6 access to generate these packets, so if it breaks the equipment, it's probably better that someone like RIPE, running Atlas probes, discovers this rather than a script kiddie out there then posting it to full-disclosure.
wouldn't it be sufficient to support the fragment header initially? hop-by-hop we expect to be severely rate limited anyway, and RH0 is probably blocked. let's be able to test the one that actually matters. cheers, Ole