mailutils-pop3d 1:3.7-1 (amd64 binary) in ubuntu focal

 GNU Mailutils is a rich and powerful protocol-independent mail framework.
 It contains a series of useful mail libraries, clients, and servers.
 .
 The GNU mailutils POP3 daemon supports the basic POP3 protocol with the
 CAPA, RESP-CODES, PIPELINING and UIDL extensions. It also supports APOP
 authentication. The user credentials for APOP can be stored in a variety
 of DBM formats. It is able to get the authentication information from
 the system user database as well as from a SQL database of arbitrary
 structure. The PAM framework can also be used for authentication
 purposes. Additionally, mailutils pop3d supports virtual mail domains and
 has TLS support via GNUtls. GNU mailutils supports the mbox, MH and
 Maildir mailbox formats.