Listing available SynthDefs

When I want to know what samples are loaded in SuperDirt, I just have to look at the starting log of SuperCollider.
Is there a way to obtain a similar list of SynthDefs that are available to use in the current session?

You could evaluate the following line in supercollider to open up the global SynthDef browser, if you select a synth there it will show you it's control parameters:;