Binary package “elpa-notmuch” in ubuntu bionic

thread-based email index, search and tagging (emacs interface)

 Notmuch is a system for indexing, searching, reading, and tagging
 large collections of email messages in maildir or mh format. It uses
 the Xapian library to provide fast, full-text search with a very
 convenient search syntax.
 .
 This package provides an emacs based mail user agent based on
 notmuch.