Currently we support the gitlab OP for issuing ID Tokens to workflows in gitlab-ci but not the gitlab OP for issuing ID Tokens to users (humans). There is interest in using OpenPubkey in gitlab workspaces: https://gitlab.com/gitlab-org/gitlab/-/issues/438790
This requires support the user auth for the gitlab OP. This should not be difficult to do.