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But it would be tricky, because there could be other obsolete worktrees, too, that silently could be deleted, too.

Please try version 19.1.

I've scheduled it for the Journal for v19.2. What exactly do you mean with "Log for" Graph window?

In what details the current implementation differs from your expected behavior?

IMHO, Git only supports "Prune obsolete worktrees" which already exists as a menu item.

Please use "Use Message for Commit" and then the interactive rebase. It highlights equally named commits and offers auto-squash commands.