I've been using this functionality for two years without incident and
it's been outstanding. In my opinion it's time to both remove the
experimental warning label and move this straight into tweakdefaults.
I agree, except that I've seen it crash sometimes. I wrote a little script to find such cases now. Here's an example: hg diff --change 7c2921a6. So we need to fix that first. Sorry I never bothered to report a bug for it.