9.3. Token Endpoint Authentication Method Registration
Per this specification, the following values have been registered in the IANA "OAuth Token Endpoint Authentication Methods" registry [IANA.OAuth.Parameters] established by [RFC7591].
Token Endpoint Authentication Method Name: tls_client_auth
Change Controller: IESG
Specification Document(s): Section 2.1.1 of RFC 8705
Token Endpoint Authentication Method Name: self_signed_tls_client_auth
Change Controller: IESG
Specification Document(s): Section 2.2.1 of RFC 8705