Google officially ends support for the AOSP Dialer and Messaging apps and will remove them from the source manifest.
I spotted this change last week but didn't think it was a big deal (because it isn't), but since it's now being picked up on by news sites (https://www.osnews.com/story/136235/google-further-guts-the-android-open-source-project-by-deprecating-the-dialer-and-messaging-apps/), let me explain why.