This was introduced by HTML#11984. The spec PR names bug 2004569 as implementation bug, but it only updates the WPTs and is closed already, hence this new bug.

Reverted this because it was causing wpt failures.

• Revert link
• Push with failures
• Failure Log
• Failure line: TEST-UNEXPECTED-FAIL | /html/dom/idlharness.https.html?exclude=(Document|Window|HTML.+) | NavigationPrecommitController interface: operation addHandler(NavigationInterceptHandler) - assert_own_property: self does not have own property "NavigationPrecommitController" expected property "NavigationPrecommitController" missing

Ah, there's android + no ship of course. I updated the expectation and I'll reland.

https://hg.mozilla.org/mozilla-central/rev/7f1657e2c77b

:jjaschke, could you consider nominating this for a release note? (Process info)

Release Note Request (optional, but appreciated)
[Why is this notable]: This allows registering a post-commit navigation handler during the pre-commit phase, to allow a multi-step navigation process.
[Affects Firefox for Android]: Yes, but only with SHIP
[Suggested wording]:
[Links (documentation, blog post, etc)]: https://github.com/whatwg/html/issues/11956

Thanks, added to the Fx148 nightly release notes, please allow 30 minutes for the site to update.
Keeping the relnote-firefox flag as ? to keep it on the radar for inclusion in the final Fx148 release notes.