You can toggle `devtools.popups.debug` preference [1] to true in about:config and DevTools should open on popups.
Unfortunately, there is some limitations, highlighted at the end of that bugzilla entry. It won't work for <a target="_blank">, while it should work for window.open usages.
Why? I am surprised as I use 3 browsers for different contexts: - ungoogled chromium for everything behind my company's SSO - firefox with an AWS theme with containers setup for each AWS account under another firefox account. - librewolf for everything else with containers syncronized under a personal firefox account
I could probably run everything under the same firefox or librewolf browser and different profiles but that way I didn't even had to setup separate launchers for the profiles. I also like that they are all visually different so I can spot them easily when switching windows.
[1]: https://www.mozilla.org/en-US/firefox/developer/
[2]: https://hacks.mozilla.org/2016/12/firebug-lives-on-in-firefo...
1. "Pause breakpoints" gets unchecked after app rebuilds and/or restarts.
2. The Ctrl+P hotkey only works on the sources tab, unlike Chrome. I just can't bear to always keep in mind what tab I'm on when using a hotkey.
Regarding Ctrl+P, there is a bug on file [2], we could easily make it so that it switches to debugger and open that search-for-file UI from there. Showing this UI on top of any panel would be a much more involved change.
[1] https://bugzilla.mozilla.org/show_bug.cgi?id=1933764 [2] https://bugzilla.mozilla.org/show_bug.cgi?id=1409544
Overall it's a pretty similar experience. Most difficult part is the habit changing of getting used to a different UI.