Qlone is a small mod for Quake III: Arena expected to bring some enhancements to vanilla Q3.
As this mod is mainly used for online games, if you want to try or use Qlone, you should install the mod on a dedicated server and on your Quake3 installation.
If you only want to give it a try, download the mod from this site or use the cl_allowDownload 1 cvar in your q3 config and join the test server: /connect my.qlone.org (the mod will be downloaded upon connection). Please note that if you have already been on this server, you should remove your qlone directory before connecting to the server to be sure to get the latest release and avoid any troubles or problems.
Qlone is developped by uZu and it's based on ioQuake3.
Unlagged is implemented following the latest info and source code published by Neil "Haste" Toronto. Unfortunately, his website is now down but one can fetch info on archive.org and the source code archive at https://gamebub.com/files/ef/unlagged-2.01-src.zip
Freeze Tag has been added based on the source code and infos published by Darrell "Doolittle" Bircsak at https://github.com/dbircsak/freeze-tag. The version number used in Qlone has been bumped to 1.52 because it's the 1.51b source code slightly modified and adapted to current version of ioquake3 with the ability to make it optionnal with the freezeTag server cvar. At the time of writing, only the server-side of FT has been added to Qlone.
InstaGib is based on infos published by Steven Conway a.k.a Coners and Malcolm Lim a.k.a CyberKewl on code3arena: TUTORIAL 37 - Instagib gameplay and TUTORIAL 39 - Server only InstaGib.