That Firebug is an extension is one of its worst features. Every version of Safari or WebKit I download has a working inspector built in. Every time I launch a

That Firebug is an extension is one of its worst features. Every version of Safari or WebKit I download has a working inspector built in. Every time I launch an archived version of Firefox, or get a new version of Firefox, I get warnings about incompatible Firebug plugins. It's a real pain when it comes to testing across multiple versions.