I have taken it upon myself to figure out how to write extensions / plugins for Firefox. At this stage, I still don’t know if those two terms are synonymous or not.
So far I’ve read through a XUL Tutorial and played with the example code. Selecting File->Open in Firefox’s File menu and then selecting a .XUL file will open and render it, as desired. I am indeed impressed with how rapidly nice UIs can be created. Also, the standard itself has a Ghostbusters reference; can’t hurt!
It gets interesting here, where you can add event handlers.
Too .. tired .. to .. go .. on