The FOSS implementation of the OpenID Connect for Identity Assurance specification, eKYC Hub, has now been updated to support the recent version of the specification, which is available here https://openid.net/specs/openid-connect-4-identity-assurance-1_0.html.
The source code repository for the eKYC Hub can be found at https://github.com/identityfirst/eKYC-Hub.