What is WebIDL and (why) is it important?

Question

The WebIDL spec is in last call and the buzz is that this is a big step for the web. However, I can't find much useful information on it and why it is important.

I understand it defines an interface but an interface for what? How does WebIDL relate to ECMAscript, JavaScript, HTML or the DOM? Will this affect the life of the humble web developer or is it for a different crowd - browser developers perhaps?

Links to articles are welcome.

Answer 1

I would say that it relates to the DOM and ways to manipulate it through languages other than JavaScript. JavaScript already has ways to manipulate the DOM, but that's not a standard, and WebIDL is probably an interface for other languages.