BIMI mark certificates.

What is a mark certificate?

BIMI (Brand Indicators for Message Identification) lets a domain publish the logo a mail client may show beside its authenticated messages. Mail providers that require evidence of trademark ownership accept a Verified Mark Certificate (VMC) or a Common Mark Certificate (CMC), issued by a Mark Verifying Authority after vetting the brand and its trademark. The logo travels inside the certificate as an SVG Tiny P/S image, and the issuers publish every mark certificate to dedicated Certificate Transparency logs listed by the BIMI Group — ctlogs.dev ingests those logs (see monitored logs) separately from the TLS certificate index. Logos are re-encoded from an allow-list before display and served from a sandboxed endpoint.