GTK Inspector missing?

[vasa1]

I'm using a live USB of Lubuntu 16.04.

According to https://wiki.gnome.org/Projects/GTK%2B/Inspector, one can run

gsettings set org.gtk.Settings.Debug enable-inspector-keybinding true

to activate GTKInspector but I get

lubuntu@lubuntu:~$ gsettings set org.gtk.Settings.Debug enable-inspector-keybinding true
No such schema 'org.gtk.Settings.Debug'
lubuntu@lubuntu:~$

Is this because I'm using Lubuntu or does this fail on other Ubuntu flavors as well?

Looking at the comments to this answer, it seems that this issue was present in Ubuntu GNOME 15.10 as well.

+++++++++++++++++

If I run

gsettings list-schemas | grep -i settings

all I get is:

org.gnome.settings-daemon.plugins.gdu-sd
org.gtk.Settings.FileChooser
org.blueman.gsmsettings
org.gtk.Settings.ColorChooser
lubuntu@lubuntu:~$

So I'm guessing that for whatever reason, GTKInspector won't be in Lubuntu 16.04 and possibly other flavors. But something is available if a gtk3 application is launched like this:

GTK_DEBUG=interactive application_name

But, according to this bug, "No such schema 'org.gtk.Settings.Debug'" error upon trying to activate GTKInspector shortcuts, users who want this need to install libgtk-3-dev.