extensions/README.md

# Extension System Development Guide]

## Where to find documentation

### Here
Documentation for extensions is [here](src/backend/doc/extensions/README.md).

### Not Here

Outdated documentation for extensions is [here](../doc/contributors/extensions/README.md).
This documentation may include some topics that are missing from the current documentation. Eventually those topics should be updated and transferred to the current documentation so that this documentation may be removed.