Pigeonhole adds support for the Sieve language (RFC 5228) and the ManageSieve protocol (RFC 5804) to the Dovecot e-mail server.

Sieve is a language for filtering incoming mail. Messages can be forwarded or sorted into separate folders. Unwanted messages can be rejected or discarded, and, when the user is not available, the Sieve interpreter can send an automated reply.

Sieve is meant to be simple, extensible, and system-independent. The intention is to make it impossible to write anything more complex (and dangerous) than simple mail filters. Unlike most other mail filtering script languages, Sieve does not allow users to execute arbitrary programmes.

Through the ManageSieve protocol, users can remotely manage their Sieve scripts without needing file system access. The server accepts only valid scripts to prevent embarrassing errors later on.

Mlmmj is a simple and slim mailing list manager (MLM) inspired by ezmlm. It works with many different Mail Transport Agents (MTAs) and is simple for a system administrator to install, configure and integrate with other software. As it uses very few resources, and requires no daemons, it is ideal for installation on systems where resources are limited. Its features include:

1. Archive, Custom headers / footer,

2. Fully automated bounce handling (similar to ezmlm),

3. Complete requeueing functionality, Moderation functionality, Subject prefix,

4. Subscribers only posting, Regular expression access control,

5. Functionality to retrieve old posts, Web interface, Digests,

6. No-mail subscription, VERP support,

7. Delivery Status Notification (RFC1891) support,

8. Rich and customisable texts for automated operations.

dovecot-libsodium-plugin provides a libsodium password hashing scheme (such as scrypt) plug-in for Dovecot.

This package provides Python bindings to use the Notmuch mail indexing and search library.

This package provides a threaded Python IMAP4 client, based on RFC 3501 and original imaplib module.

A flexible, extensible mail retrieval system with support for POP3, IMAP4, SSL variants of both, maildirs, mboxrd files, external MDAs, arbitrary message filtering, single-user and domain-mailboxes, and many other useful features. This is a fork derived from getmail 5.14, aimed at Python 3 compatibility.

The hyperkitty Django app provides a web user interface to access GNU Mailman3 archives, and manage it. This interface uses django, and requires some configuration.

neatmail is a noninteractive mail client. It generates a listing of the messages in a mailbox in mbox format and executes a list of ex-like commands on it.

GNU Mailman is software for managing email discussion and mailing lists. Both users and administrators generally perform their actions in a web interface, although email and command-line interfaces are also provided. The system features built-in archiving, automatic bounce processing, content filtering, digest delivery, and more.

Email::Address::XS implements RFC 5322 parser and formatter of email addresses and groups. Unlike Email::Address, this module does not use regular expressions for parsing but instead is implemented in XS and uses shared code from Dovecot IMAP server.

Mew (Messaging in the Emacs World) is a user interface for text messages, multimedia messages (MIME), news articles and security functionality including PGP, S/MIME, SSH, and SSL.

Guile is the GNU Ubiquitous Intelligent Language for Extensions, the official extension language of the GNU system. It is an implementation of the Scheme language which can be easily embedded in other applications to provide a convenient means of extending the functionality of the application without requiring the source code to be rewritten.

GCC is the GNU Compiler Collection. It provides compiler front-ends for several languages, including C, C++, Objective-C, Fortran, Ada, and Go. It also includes runtime support libraries for these languages.

GNU Binutils is a collection of tools for working with binary files. Perhaps the most notable are "ld", a linker, and "as", an assembler. Other tools include programs to display binary profiling information, list the strings in a binary file, and utilities for working with archives. The "bfd" library for working with executable and object formats is also included.

Guile is the GNU Ubiquitous Intelligent Language for Extensions, the official extension language of the GNU system. It is an implementation of the Scheme language which can be easily embedded in other applications to provide a convenient means of extending the functionality of the application without requiring the source code to be rewritten.

Binaries used to bootstrap the distribution.

Headers of the Linux-Libre kernel.

Tarballs containing all the bootstrap binaries

Guile is the GNU Ubiquitous Intelligent Language for Extensions, the official extension language of the GNU system. It is an implementation of the Scheme language which can be easily embedded in other applications to provide a convenient means of extending the functionality of the application without requiring the source code to be rewritten.

scdoc is a simple man page generator written for POSIX systems in C99.

libpipeline is a C library for manipulating pipelines of subprocesses in a flexible and convenient way.

GNU help2man is a program that converts the output of standard "--help" and "--version" command-line arguments into a manual page automatically.

man2html is a command-line tool for converting man pages into HTML format.

mandoc is a suite of tools compiling mdoc, the roff macro language of choice for BSD manual pages, and man, the predominant historical language for UNIX manuals. It is small and quite fast. The main component of the toolset is the mandoc utility program, based on the libmandoc validating compiler, to format output for UTF-8 and ASCII UNIX terminals, HTML 5, PostScript, and PDF. Additional tools include the man viewer, and apropos and whatis.