I sent out the mapping of mailing lists as part of the migration. Currently, projects that are considered "Kernel" are all forwarded to kernel-dev. All other mailing lists (not including security, Jenkins, Infrastructure, Integration, discuss, TSC, dev, documentation, marketing, project proposals and release) are forwarded to app-dev.
If you are not subscribed to kernel-dev or app-dev, you will NOT receive an email. Email sent to the old lists is being forwarded to the new lists automatically. Please subscribe to kernel-dev or app-dev to receive emails.
Sadly, we can not edit the subgroup page on Groups.io. It just lists the mailing lists. It does however indicated which groups are "locked" with a padlock. The lists that are locked will not receive email and are forwarded to kernel-dev or app-dev. We can add a "category" to each of the lists, though. I am not sure if or how that may help though.
Here is the current mapping of lists that are forwarded: