ruby-notmuch 0.26-1ubuntu3 (s390x binary) in ubuntu bionic

 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 a Ruby interface to the notmuch
 functionality, directly interfacing with a shared notmuch library.