This is a simple plugin to require users to provide comments when adding changes to a wiki page. User customizable options may be added in the future, but for now it works just fine as-is.
To install, simply run "python setup.py bdist_egg". The resulting egg file will be located in the 'dist' folder after it is built. Copy this egg file to the plugins subdirectory of a trac environment, and restart your webserver to ensure that the new plugin is loaded.