Anubis. This is in place to keep the software as stable as possible - without it, it would simply not function due to the amount of bots attempting to scrape data.
This software processes some network data, namely the client's IP and browser user-agent. We do not log these and you can very easily use a VPN, Tor, or User-Agent changing browser extension, to improve privacy if needed. This software also has the ability to use DNSBL, which is known to block these VPN/Tor users. It has been configured to not use this.
Depending on your outlook, the only potential breach of privacy is the fact that it requires you to use JavaScript. This is absolutely required for its functionality and doesn't actually impact privacy whatsoever - it is 100% possible to track a user without it and the only thing it's really doing is answering a proof-of-work challenge, sending network requests, and updating the client's HTML. That is all that the client-side JS is used for, and can be confirmed by looking at its source code.