Install OSUS on an IPv6 cluster, and ensure it works as a periodic or https://github.com/openshift/cincinnati-operator presubmit. We are not responsible for things like "does quay.io support IPv6?", because IPv6-only clusters would need to have release images available in a registry (possibly a local mirror) that supported access over IPv6, or CRI-O wouldn't be able to retrieve those images to run the cluster. So it's fine to mock any external dependencies that cause trouble, or point at some alternative available in the test environment. But if there is a problem in Cincinnati or its operator that breaks their functionality on IPv6, we want to hear about it, so we can fix it. We aren't responsible for integration on a particular deployment, but we want to ensure that code we own doesn't break if someone else does try and perform that kind of integration work.

The OSUS testing also covers the app-interface-deployed Cincinnati that backs https://api.openshift.com/api/upgrades_info/graph , without having to directly test that deployment. If OSUS is capable of running in an IPv6-only cluster, that app-interface deployment will also be capable of running in an IPv6-only cluster too, because the app-interface deployment is bare Cincinnati without a controlling operator (app-interface stands in as the operator). We do not need to actually configure the app-interface deployment to serve IPv6; that would be independent work that we may or may not be asked to do later, via a separate Feature.