`notmuch-multipart/alternative-discouraged` and
`notmuch-show-all-multipart/alternative-parts`.
+ Note notmuch-show-print-message (bound to '#' by default) will print
+ all parts of multipart/alternative message regardless of whether
+ they are currently hidden or shown in the buffer.
+
Emacs now buttonizes mid: links
mid: links are a standardized way to link to messages by message ID