The official Spanner CLI has been released:
https://cloud.google.com/spanner/docs/spanner-cli

Although it does not appear to be open source at this time, I believe—based on some undocumented behaviors—that it is derived from cloudspannerecosystem/spanner-cli.

Could you please clarify the relationship between this repository and the official Spanner CLI?
Will this relationship be documented anywhere?

Additionally, what are the plans for the future development of cloudspannerecosystem/spanner-cli?