How does a mailbox provider support and display BIMI logos?

If you’re wondering exactly how a mailbox provider like Yahoo, Google, Comcast or Fastmail might implement support for decoding and displaying BIMI (Brand Indicator for Message Identification) logos in or near the inbox, then I’ve got you covered. TL;DR? It boils down to: Validate the email, find the BIMI record, validate the logo, then decide whether or not you trust the sender enough to display…