Hi leo, I have the same setup as you do (debian stretch+mutt).
On [1], one can read: This package is built with the NeoMutt patchset, which includes a number of additional features compared to the stock Mutt. Which I don't interpret as you do; debian's mutt is compiled with the NeoMutt patchset, but it's mutt and not neomutt. So you have mutt ;) Best, Steve [1] https://packages.debian.org/stretch/mutt
