FIrebug was a chrome extension that was used before but now it is not supported and if you still want to use it then probably you will have to downgrade the chrome version.
Firebug is discontinued open-source web browser extension. It was used to inspect element.
There is another version i.e. Firebug Lite.
You can use ChroPath. https://chrome.google.com/webstore/detail/chropath/ljngjbnaijcbncmcnjfhigebomdlkcjo
Hope this information helped.