Can somebody explain to me what that means, in simpler words?

Will I be able to remote-control my mozilla from a perl script? That would be very usefull to me. It would mean I can use it together with Test::Simple (and others) to do testing of a project that involves Perl as well as javascript code. I know that exists for IE, but if I can remote-control Mozilla instead, I don't need to keep a machine under windows.

Or does it mean that I will be able to use Perl instead of Javascript, but it will only work for those clients who have Perl installed?

I looked through the XPCOM article and quite frankly couldn't make heads nor tails of it.