Open Source Hotline
This page will contain links to any software for Hotline made open source. Separated into sections for Clients/Servers/Trackers. (I will also attempt to tag with language written in to make life easier),
Clients
Filetalk (Ruby) [Source] - Last Updated April 2010
Hotline (SwiftUI) [Source] - Updated regularly
Mobius (CLI) [Source] - Updated regularly
Fidelio (GTK+) [Source] - Abandoned, last updated in September 2002
GtkHX (GTK+) [Source] - Abandoned, last updated in February 2004
Underline (Carbon / Classic / Win32) [Source] - Abandoned, last updated in December 2003.
OpenHLC + Source - Abandoned, last updated in February 2000, as one of the first open-source Hotline clients.
Servers
Mobius (CLI) [Source] - Updated regularly
HXD for OS X [Source] - Abandoned, last updated in October 2001
Trackers
Amoeba's HLtracker (CLI) (Ruby) [Source] - Abandoned, last updated in February 2020