The doctrine bridge contains the interface Symfony\Bridge\Doctrine\RegistryInterface.

• The only implementation of that interface that I know of is Doctrine\Bundle\DoctrineBundle\Registry which has been triggering deprecation errors for each method defined by the interface for 6.5 years now: doctrine/DoctrineBundle@89c7e14

• Its parent interface Doctrine\Common\Persistence\ManagerRegistry is an equal replacement.

• I haven't found a single reference to the interface in the symfony codebase (except for the one I've removed in [Messenger] Use ConnectionRegistry instead of RegistryInterface #32354).

I find the very existence of this interface highly confusing and suggest to deprecate the interface in 4.4 and remove it with Symfony 5.