git delete branch; git delete commit
git delete commit
git rebase -i SHA_of_commit_to_delete^ drops you into the usual screen, three you can change
drop in the first line (or any others) to just delete that commit.
Generally, On undoing, fixing, or removing commits in git seems like The README for that.
git delete branch
git branch -d some-branchdeletes a local branch
git push origin --delete some-branchdeletes a remote branch
(as usual, remembering that branches are pointers to commits)