Public Duels plugin on Spigot. More info and download here: https://www.spigotmc.org/resources/multiarena-duels-1v1.44820/
If you want to contribute, please ping me on my Discord and ask. If it's a good feature idea or bug fix, I'll probably end up approving your PR. I ask you try to follow similar stylings to what exists already.
If it's not a feature that fits well with the plugin, it may be denied. If the styling is really bad or something does not work, I may request changes.
It's a Maven project, you should be able to get everything you need to get started by doing mvn install (or letting an IDE handle it for you).
