Arena clients are what run all the matches on AI Arena.
They request their next match to play from the aiarena.net website and download all the relevant information from there. They can also be configured for running local matches between bots you supply yourself.
Debian Buster with standard Linux libraries
Python 3.9 with these libraries installed: https://github.com/aiarena/aiarena-docker/blob/master/requirements.txt
Please ask on discord if you require other libraries or are unsure of anything