Comment 17 for bug 483556

I think adding two environment variables would do the trick. We don't want to depend on GConf. When GSettings are available via Python we might want to use those, but envvars are a good start imho. So:

ZEITGEIST_DEFAULT_EXTENSIONS=override the variable _zeitgeist.engine.constants.DEFAULT_EXTENSIONS

ZEITGEIST_EXTRA_EXTENSIONS=extra extensions to load on top of the ones specified by _zeitgeist.engine.constants.DEFAULT_EXTENSIONS

The format of these variables should just be a no-space comma separated list of module.class names line we already have in _zeitgeist.engine.constants.DEFAULT_EXTENSIONS. Fx adding the following lines to my .bashrc would enable the frobnicator- and Tracker event miner extensions:

ZEITGEIST_EXTRA_EXTENSIONS=frobnicator.zg_extensions.ZGFrobicatorExtension,tracker.zg.EventMinerExtension