Hey Paul,
You may instead be thinking of Bitwarden_RS (aka written in Rust) which is the previous name of the Vaultwarden project.
https://hub.docker.com/r/bitwardenrs/server
The project was renamed due in part to prevent any user confusion between the two and further separate the offical release from the unofficial 3rd party rewrite.
As you can see the image in docker hub is not the same name but instead bitwardenrs and released from the bitwardenrs developer and not the Official Bitwarden docker repo.
I believe David was simply trying to clarify the point further for any users who may reference this posting in the future as there have been a sub-set of users who are not aware of the differences between the two.