These are discussed here, but didn't make it into either release:
See PHI592. A diff with 600MB of videos required more than two hours to turn into an email patch, which exceeded the task lease duration and cascaded into various other kinds of problems. This is somewhat adjacent to T11767.
See PHI580. An install would like write API access to object relationships (depends on, fixes, etc). This is complicated, but perhaps plannable, and we may be able to put a reasonable facade with partial support into the upstream.
See PHI617. This appears to report a trivial bug in the new Harbormaster log UI, where clicking the chevron icon has different behavior from clicking the text ("Show More Above") next to the chevron icon. The chevron behavior is broken.
See PHI619. This appears to report a trivial bug where executing a Herald test console run when an active rule uses a "Content Source" field fails because test runs from the console don't have a content source.
See PHI615. This reports a bug where "Lease Working Copy" build steps incorrectly report "Built Instantly" even when they didn't. This is probably not harder than it looks.
See PHI483. The available actions from "Changes Planned + Draft" (and maybe "Abandoned + Draft") are currently too permissive. Fewer actions should be available; particularly, "Accept" should not be available and the actions should generally be more similar to the actions available from "Draft".
See PHI285. An install would like a way to monitor changes to Herald rules. This mostly needs planning. The actual implementation may not be difficult, it's just not clear if "Herald rules for Herald rules" are the best approach.
See PHI285. Mail about Herald rules does not actually include a link to the rule.
See PHI590. See T13128. The policy tag in the header of Phriction documents could be more useful than it currently is. This is potentially the tip of a nest of vipers, but improving the Phriction behavior narrowly would be a good first step.
See https://discourse.phabricator-community.org/t/unable-to-create-owners-package-with-same-path-in-multiple-repositories/1400. I was able to reproduce this.
See T13132, an issue with arc download and CSP changes.
See PHI604. See also T13126. An install is hitting the "large blame does not degrade gracefully" issue mentioned in that task, and would also like a way to selectively disable blame (which I was leaning toward implementing but don't think got written down anywhere).
Internally, it would be nice to better document the Phabricator query layer. (Ongoing; see T13133.)
See PHI251. This requests an "Ignore generated changes." option for Owners. There may not be a direct path to this today, but this is almost certainly a plannable feature. This is a bit rough.