I found out some years ago that emails that have the fancy features like plane tickets embedded or tracking information are all done with JSON-LD in the emails.

I found out some years ago that emails that have the fancy features like plane tickets embedded or tracking information are all done with JSON-LD in the emails. AFAIK only gmail supports it, though. EDIT: some more info about it: https://www.emailonacid.com/blog/article/email-development/schema-markup-gmail/ https://www.emailonacid.com/blog/article/email-development/s...