Tracking notable behavior changes in the changelog

[GeigerJ2]

We've been going back and forth on this (in #7319 (comment)), so here's a summary of the two approaches. The auto-generated commit list stays as the baseline in both cases; the question is how we capture the curated prose for notable behavior changes (the kind that ended up in v2.8's "Behavior changes" section).

A: Git trailer (Behavior-Change: in the commit message)

• ✅ Travels with the commit through rebase and cherry-pick, so patch releases get it for free
• ✅ No merge conflicts
• ✅ Extractable in one shell command (git log --pretty=format:'%(trailers:key=Behavior-Change,...)')
• ❌ Developer-facing artifact (commit message), not user-facing documentation
• ❌ Easy to miss during review (no file-level diff to prompt reviewers)
• ❌ Hard to enforce without custom tooling
• ❌ Higher barrier for external contributors unfamiliar with trailer conventions

B: Continuous CHANGELOG.md ("Unreleased" section, updated per PR)

• ✅ User-facing documentation, written where users actually look
• ✅ Visible in the PR diff, so reviewers naturally ask "does this need an entry?"
• ✅ Lower barrier for contributors (just add a line to a familiar file)
• ✅ Already a common convention in many projects
• ❌ Doesn't travel with cherry-picks; needs manual re-edit on release branches
• ❌ Potential merge conflicts (low risk with our team size)

Feel free to vote with emoji reactions, so we can already get everybodies opinion:

• 🚀 for A (git trailer)
• 👍 for B (continuous CHANGELOG.md)

[GeigerJ2]

@khsrali @agoscinski @mbercx @danielhollas @edan-bainglass

I took the freedom to already go for Option B in PR #7351, as it's a prime example of a notable behavior change. Hope that's OK for you, if not, please voice your concerns here (and we can always revert / drop it again with a follow up). Wanted to avoid actually having nothing in place and instead bikeshedding this forever :)

[mbercx]

Wanted to avoid actually having nothing in place and instead bikeshedding this forever :)

That is a great idea in our context. :)

[khsrali]

Agreed with continues changelog. 🚀
One more thing -slightly related- worth mentioning here, is versioning the main branch: #7365