Breaking: #68081 - Ext:openid moved to TER 

See forge#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.