Firebug is not working on Mozilla version 52

Question

Today i have installed a new version(52) of firefox in machine and add the extension firebug .but it not showing in toolbar. i have restarted several times still no luck and

Answer 1

Firebug is officially discontinued. New installations of Firefox have multi-process enabled. With that the Firefox DevTools are opened instead of Firebug when you click the Firebug button and a notification is shown giving a short explanation:

You can get Firebug back by deactivating the multi-process feature, though this is only a short-term solution, as multi-process will be mandatory at some point.