They say they will stick with Trac for dealing with issues. I understand that for managing the ports collection, but are they planning on keeping "base" issues (i.e. the application code) off the github as well?
I don't know how well different repos and issue trackers interop, but it seems like an open-source solution like gitlab would offer the (potential for) customization/integration more readily than github.
I'm sure they just desire a turn-key solution and don't want to manage a whole new project, but maybe, one day, they'll want to unify the experience again.