NeoMutt is provided as a separate package in -current/snapshots. The first release containing it will be 6.1.
The Mutt and NeoMutt packages don’t coexist, so remove Mutt first if installed:
# pkg_delete mutt
Then install NeoMutt, choosing from the list of pre-built packages:
# pkg_add neomutt Ambiguous: choose package for neomutt a 0: <None> 1: neomutt-20161028 2: neomutt-20161028-gpgme 3: neomutt-20161028-gpgme-sasl 4: neomutt-20161028-sasl Your choice:
# pkg_add -u neomutt
# pkg_delete neomutt
To install the main dependencies for building NeoMutt and documentation:
# pkg_add docbook-xsl lynx gettext
Now you can follow the guide for building NeoMutt.
Alternatively, checkout/update the ports tree and build in the usual way (NeoMutt is in /usr/ports/mail/neomutt).
These instructions will help you install all the dependencies you’ll need to debug NeoMutt.
Now you can follow the guide for debugging NeoMutt.