Breaking: #68081 - Ext:openid moved to TER

See Issue #68081

Description

The former core extension openid has been removed from core code and is now available as optional extension from the TER.

Impact

Login to TYPO3 backend via openid fails until the extension is installed from TER.

Affected Installations

Instances using backend login via openid.

Migration

An upgrade wizard in the install tool can be use to download and install the extension.