Quick update, we are working hard to get the service broadly available in the very near future and continue to work with folks regarding inclusion in the Limited Preview on a case-by-case basis.
For those looking for KB information on where Azure Code Signing's Root CA and signing is enabled for the /INTEGRITYCHECK scenario, please refer to KB5022661—Windows support for the Azure Code Signing program - Microsoft Support. The Azure Code Signing Root CA (Microsoft Identity Verification Root CA 2020) for publicly trusted code signing is included in the Microsoft Root Certificate Program (List of Participants - Microsoft Trusted Root Program | Microsoft Learn).
Please reach out to us with your questions or interest in our service at AzureCodeSigningTAP@microsoft.com