TorBlock was added in to the 2.0.9 CVS source code on 12/20/06.
TorBlock was later removed on 3/29/2010 (SVN revision r20973 for v2_0branch, and r20975 for trunk) and is no longer part of any future releases
The reason for removal is that it wasn't effective at preventing abuse. It only prevented full joins, so abusive users were still able to disrupt play via Tor (such as preventing any user from joining). Also, the URL we used in the plugin was no longer functional. Instead of swapping the URL for a new one every time it changes, and instead of changing the plugin to make use of TorDNSEL, we decided it was better to suggest using a firewall solution such as iptables.
When loaded TorBlock loads up the TOR master IP list from http://moria.seul.org:9032/tor/status/authority, and will from then on disconnect all users from any of those IP addresses. The TOR network is not intended for game play use and is generally only used in BZFlag for Server Spamming or other disruptive effects. TorBlock will automatically update its ban list every hour with new IPs. TorBlock works independently of the built in Banfile capability of BZFS so it will automatically allow users from blocked IPs as soon as they are removed from the TOR master list.
TorBlock was the first plug-in to do a dynamic ban feature that pulled from a central web repository. It was made in response to a Tor Based attack on the popular game servers.