Clean up local branches

1. List all local:

   git branch

2. List merged:

   git checkout main
   git branch --merged

3. Remove all outdated branches with:

   git branch -d <old-merged>

4. List not merged:

   git branch --no-merged

5. Force remove abandoned (careful!):

   git branch -D <old-abandoned>

Clean up references to remote branches

1. List all remote:

   git branch -r

2. Prune staled remote branches:

   git fetch -p