Does this work on Google Chrome?
You can't do much more than changing the theme though, as Chrome window is managed mostly by its own rendering engine.
You can also make it run in Chrome, via GTK Broadway https://developer.gnome.org/gtk3/stable/gtk-broadway.html
broadwayd :5
GTK_DEBUG=interactive GDK_BACKEND=broadway BROADWAY_DISPLAY=:5 gnome-calculator
Then go to http://127.0.0.1:8085 to see the inspector. Sadly, the calculator itself won't be visible (it would have been without the debugger).You cannot make Chrome render in Chrome this way, though, as it complains about lack of X display available.
"You can attach it to Chrome: https://imgur.com/n8Mf7J3
You can't do much more than changing the theme though, as Chrome window is managed mostly by its own rendering engine."