The sqlite3 package is required for python-2.5 and earlier (it is already included in python-2.5 and later, but the version in python-2.5 has nasty bugs)
The simplejson package is required for python-2.5 and earlier (it is already included as json in python-2.6 and later)
Jinja2 is a general purpose templating language and is used by Buildbot to generate the HTML output.