Hi Tim Harader,
Yes, to get free access to Azure DevOps including the Basic+Test Plan for your GitHub Enterprise users, your GitHub Enterprise tenant must be connected with Azure DevOps through Microsoft Entra ID Single Sign-On (SSO). This setup enables GitHub Enterprise Cloud users managed via Entra ID to be detected automatically and access Azure DevOps services without additional per-user charges
Reference
Combined use of GitHub Enterprise and Azure DevOps - GitHub Docs
GitHub integration overview - Azure DevOps | Microsoft Learn
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