Finally fixed one of my last mu4e #emacs [https://social.yakshed.org/tags/emacs] gripes:

https://git.bascht.space/bascht/dotfiles/commit/f587c79a08f7b65bb3f10c61a2da423e256ad376 [https://git.bascht.space/bascht/dotfiles/commit/f587c79a08f7b65bb3f10c61a2da423e256ad376]

Emacs will now compose the From: address from my catchall address the email was received at. \o/