I’m utterly convinced overloading the term “open” was a very bad mistake in terms of how much confusion it created. Yes, “open-source” in the OSI definition means open to read, but also open to modification and redistribution. Having to make the distinction and explain the difference with “source available” is in itself a failure in communication.
They’ve been moving more and more out of AOSP into their Play Services for a good while now. However I suspect OP was referring to their announcement that they’ll require developer verification, and apps to be signed with a certificate they issue, for any app install on a verified device (read any device sold with the Play Store). Long story short, no more building and distributing APKs without Google knowing who you are and that your app exists.
https://android-developers.googleblog.com/2025/08/elevating-android-security.html