Playing as the Yor (for the first time in a long while) on 1.61, I researched the Interstellar Banking tech. In the tech tree, that tech is supposed to unlock the Starbase Promenade and Interstellar Embassy starbase improvements. After researching it, the Interstellar Embassy became available to build on my cultural starbases, but the Starbase Promenade is not available on my economic starbases. Bug?
I don't recall it being reported before, and I don't see it being mentioned as being fixed in the 1.7 beta.