Domain-based Message Authentication, Reporting, and Conformance (DMARC) is an email authentication protocol first published as an RFC with Informational status in RFC 7489 - https://datatracker.ietf.org/doc/html/rfc7489
This is the github repository for the IETF DMARC Working Group's work to update the core DMARC specification.
The working group's charter is here - https://datatracker.ietf.org/doc/charter-ietf-dmarc/