Updated the TrueNAS 12 section to account for device_rebuild (sequential reconstruction in LBA order, not to be confused with sequential scrub/resilver, which is an optimization that does not require a feature flag) and zstd compression.
Updated the resource for FreeNAS 11.3. The only addition is feature@spacemap_v2, which I consider the first fundamentally incompatible new feature since the 9.10 days. Device removal may have a shot at that title, but it's a niche thing and pools aren't suddenly incompatible if you accidentally upgrade them - it's only after removing a device that compatibility is broken.
It turns out that selectively enabling features on import is even less fun than it sounds when, say, going from none to something that Ubuntu 18.04 can use: You have to specify -o for every feature, which gets old rather quickly.