Is there any way how to enable opening of devtools on all new tabs? I'd like to have devtools opened to be able to comfortably debug popup windows.
Chrome added the option to "Auto-open DevTools for popups" in early 2016. I'm seeing the option in Chrome 51.
Open DevTools Hit F1 to open settings Scroll all the way to the bottom, and the option is under "DevTools"
Not sure about Firefox at the moment, but I could not find anything that could lead to a positive response.
Dmitry Kulikov has developed a plugin for Firefox that does exactly this. You can find it here: https://github.com/dmitry-kulikov/firefox-devtools-auto-open and can be installed from the firefox add-on store here: https://addons.mozilla.org/en-us/firefox/addon/devtools-auto-open
From my experience it does not bind to the new tab from the start. As such you might miss some network entries. I expect this is due to this being an add-on and not natively implemented.
来源：https://stackoverflow.com/questions/38640575/how-to-force-firefox-to-open-devtools-on-each-tab