forgejo/templates/user/auth/oidc_wellknown.tmpl

{
    "issuer": "{{AppUrl | JSEscape | Safe}}",
    "authorization_endpoint": "{{AppUrl | JSEscape | Safe}}login/oauth/authorize",
    "token_endpoint": "{{AppUrl | JSEscape | Safe}}login/oauth/access_token",
    "userinfo_endpoint": "{{AppUrl | JSEscape | Safe}}login/oauth/userinfo",
    "response_types_supported": [
        "code",
        "id_token"
    ]
}