Akonadi is the Systemd or Pulseaudio of KDE community.
Andrew Clayton, a Fedora user and kernel contributor, is using Claws Mail and here is why: I like to think of it as a graphical Mutt.
There's even project hosting and repositories like COPR to make your code and builds available quickly to the community.
With Fedora's complete set of open source languages, tools, and utilities, everything is a click or command line away.
The Fedora logo is a trademark of Red Hat, Inc.
All of the software provided with Fedora is open source and free to download and use.