The conversation of migrating or bridging mailing lists to this forum hasn’t been advanced much because 100% of the technical time is now focused on the old forum migration and then will be focused on the Help & Support site transition.
Some people have already expressed their interest in moving from a mailing list to here, and we have started experimenting with enabling the creation of new topics by email in #general and #site-feedback categories, so people can use the forum as a mailing list.
Message mirroring or migration is a separate conversation that would need to happen if it’s a need for people (instead of leaving the mailing list archive and start fresh here).