It'll be part of Google Play "Protect", part of "gapps" not AOSP. Manufacturers have to ship all of gapps or none. Its not clear if this will block installs/updates, add a nag screen occasionally or fully block running these apps/disable them.
This is the equivalent of Apples Notarization which they just used to block apps after the EU told them to allow users to install apps.
I doubt its about a few dollars from developers. They'll say it's about contacting devepers. But I think it's really about control over who can publish apps, force them to agree to weird T&Cs and allow Google to exclude people.