YugabyteDB has PostgreSQL on top of Spanner architecture and is apache2 licensed (I work there).
No, it's all open source. YugabyteDB Anywhere is just automation & 24/7 core engineering support. All db features are open source. You can re-create Anywhere without needing to touch c/c++.
Note: All features have always been open source (besides incremental backup which will be soon).