mailutils binary package in Ubuntu Focal amd64

 GNU Mailutils is a rich and powerful protocol-independent mail framework.
 It contains a series of useful mail libraries, clients, and servers.
 .
 This package contains the GNU mailutils versions of dotlock, frm, from,
 maidag, mail, messages, mimeview, movemail, readmsg and sieve. They are
 capable of speaking POP3, IMAP, mbox, MH and Maildir.
 .
  dotlock -- lock mail spool files.
  frm -- display From: lines.
  from -- display from and subject.
  maidag -- the mail delivery agent.
  mail -- the standard /bin/mail interface, mail sender and reader.
  messages -- count the number of messages in a mailbox.
  mimeview -- display files, using mailcap mechanism.
  movemail -- move messages across mailboxes.
  readmsg -- extract selected messages from a mailbox.
  sieve -- a mail filtering tool.

Source package