Opera Open Sources Dragonfly
netux writes to mention that Opera has released Dragonfly, their answer to Firebug, as an open source project under the BSD license. The release features a complete architectural overhaul using a modern version of the Scope Protocol (STP-1), a Mercurial repository on BitBucket, and a Wiki to get the ball rolling. "This is Opera’s first full open source project, so there will be a learning curve. We ask you to bear with us while we get everything up and running and policies in place. Coming from a closed source background there are some hurdles to overcome, such as the current bug tracking system being on a closed server. We hope to migrate to an open bug tracking system as the project gets on its feet."
I propose a new betting pool: How long until an Opera fanatic claims Opera developed Dragonfly first, and Firebug is just a ripoff.
Actually before Dragonfly opera had a different set of developer tools, called Developer Console
Opera Developer Console
Opera now includes a developer console that can be added into the browser with many new features. The developer console includes new tools including DOM inspector, JavaScript inspector, CSS editor and HTTP header inspector.
Which were released 15 Nov, 2006, and on my research that is a year or so before firefox.
Link: http://dev.opera.com/tools/