Following agreements with legal and compliance teams, the attached powerpoint describes the desired user experience of extension use: essentially the hard-to-locate switch to enable use of external repositories is superseded with a duo of much more visible views: 

• one displayed during onboarding (https://bugreports.qt.io/browse/QTCREATORBUG-32579)
• one displayed when entering extension mode (only if the user has not completed onboarding and has not forbidden Qt Creator to display this screen again)

extensions-enablement-v2.pptx