This is my PowerShell variant for squash merge repos:

    function Rename-GitBranches {
        git branch --list "my-branch-prefix/*" | Out-GridView -Title "Branches to Zoo?" -OutputMode Multiple | % { git branch -m $_.Trim() "zoo/$($_.Trim())" }
    }

I'm a branch hoarder in a squash merge repo and just prepend a `zoo/` prefix. `zoo/` generally sorts to the bottom of branch lists and I can collapse it as a folder in many UIs. I have found this useful in several ways:

1) It makes `git rebase --interactive` much easier when working with stacked branches by taking advantage of `--update-refs`. Merges do all that work for you by finding their common base/ancestor. Squash merging you have to remember which commits already merged to drop from your branch. With `--update-refs` if I find it trying to update a `zoo/` branch I know I can drop/delete every commit up to that update-ref line and also delete the update-ref.

2) I sometimes do want to find code in intermediate commits that never made it into the squashed version. Maybe I tried an experiment in a commit in a branch, then deleted that experiment in switching directions in a later commit. Squashing removes all evidence of that deleted experiment, but I can still find it if I remember the `zoo/` branch name.

All this extra work for things that merge commits gives you for free/simpler just makes me dislike squash merging repos more.