So there are five different ways to do email with HTML in it. Only one of them is correct. Commercial entities should know better.
- Don’t include a text/plain (Walgreens, GNS3)
- Include a text/plain that is just a duplicate of the text/html(IFTT)
- Include a text/plain that is the text of the text/html, with all the href links, which are useless in a text/plain context(Zillow, Royal Caribbean)
- Include an actual plaintext message in the text/plain, but the content of that message is just their legalese and a message to go to a particular URL if your mail reader can’t display text/html(Chase, Adobe)
- Include a text/plain version that contains exactly the same text as the text/html version, but without any of the HTML markup, making it actualy readable to mere human beings.(Patreon).