closure inspection abilities, like the someFunction.%closureVar command line syntax.Playing around with the UI, this is what comes to mind, but I'm sure there are more: There are lots of small features that Firebug has that the built-in tools don't. There's also a migration guide explaining the differences between Firebug and the Firefox DevTools. Once multi-process Firefox is enabled, pressing F12 or clicking the Firebug button opens the Firefox DevTools and with the Firebug theme. Since Firefox 48 there's also a Firebug theme that looks like the Firebug extension, letting you feel at home if you're used to Firebug. There are more things missing, which are tracked in a bug report filed for all the gaps between Firebug and the Firefox DevTools.Р”Р‡irebug is now built on top of the native developer tools. No always-on mode and activation per domain (instead of per tab).Can't add cookies, just edit existing ones.Missing autocompletion for several CSS properties.Can't search within responses of network requests.No toolbar buttons to toggle the tools or the Inspector.No multi-line command line in the Web Console (though they have Scratchpad and a 'smart-multi-line' command line).Can't search within multiple files in Style Editor.

Missing autocompletion for non-enumerable properties in the command line.Missing a DOM side panel in the Inspector.Missing an events side panel in the Inspector (though events are displayed within the DOM structure).Can't stop the script execution on DOM mutations, XHRs, or cookie changes.The differences have mainly reduced to the following points: Firefox's native developer tools have come a long way since this question was written.

Install firebug for firefox 46