These plugins can be accessed through the "module" class commands of Kninja. Please note that they require level 10 authorization.
A web-based list of these plugins will appear magically sometime in the future, hopefully. However, a very basic listing is at : http://kman.me.uk/kpr/. The *info.txt file is the information regarding the module, including the MD5 hash. The *.py file is the actual module. Enter the module name to install (without info.txt or .py).