[paradox460]

JJ let's you have multiple "versions" of the same branch, although not directly. Typically it comes about when you've made changes and someone else has made changes, and the conflict resolution can't happen cleanly, due to each path taking a difference, unreconcilible approach. You'll have to resolve those and unify the different "branches", but it's no harder than any rebase in git land (generally easier because jj's conflict markers are even better than git's 3 part system)