libmu-dbm9 1:3.15-3build1 (amd64 binary) in ubuntu lunar

 GNU Mailutils is a rich and powerful protocol-independent mail framework.
 It contains a series of useful mail libraries, clients, and servers.
 .
 This is GNU's Mail abstraction library dbm support component. This library
 allows programs to hook into a single library for many different types of
 mail backends. The following backend stores are currently provided: mbox,
 mh, maildir, dotmail, pop3, imap4.