git contribute [branches]
The contribute command makes some of your branches contribution branches.
Examples
Make the current branch a contribution branch:
git park
Make branches "alpha" and "beta" contribution branches:
git park alpha beta
Check out a remote branch (that exists at origin but not on your local machine) and make it a contribution branch:
git contribute somebody-elses-branch
Convert the current contribution branch back to a feature branch:
git hack
Convert the contribution branches "alpha" and "beta" back to a feature branch:
git hack alpha beta