UPDATE ......Confluence has now been updated to version 9.2.6. Please see following page for details and feedback about changes:
Updates
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The TEIP service proxies multiple external identity providers to 1 single persistent SAML2 IdP. This allows VOs and federations to use 1 endpoint for all Guest/External Id scenarios, while at the same time allowing the endusers to choose the service they prefer.
TEIP functional overview. Note that Authentication sources shown are examples, and may not be present in actual setup.