BIMI records
BIMI uses DNS records to point mail systems to brand logos; the talk notes that DMARC must be configured before the logo display can be used.

Brand Indicators for Message Identification publishes brand information beneath _bimi as TXT records. Mail clients can use this data when they decide how to display a sender’s identity.
It is a more formal example of DNS as a metadata layer: the record is not a host address but a statement about brand presentation and mail policy.
Primary source: https://bimi.agari.com/