Git can host multiple DAGs in the same repo with git checkout --orphan
command. A frequently cited use case this feature of git is to keep separate a branch for doc
Another possible use of this is for combining multiple repositories into one. A few examples:
In these cases you will have two separate DAGs in the same repository before they are merged into a single unified tree. Thus this is not as much a long-term use, but an action that will temporarily pass through the state of having separate DAGs in the same repository.