(sorry for the stupid summary, but that's what happens)
If you try to launch it, something in python makes it break:

INFO    : Caching gsettings: <gtweak.gsettings._GSettingsSchema: org.gnome.desktop.interface>
Traceback (most recent call last):
  File "/usr/bin/gnome-tweak-tool", line 84, in <module>
    MainWindow()
  File "/usr/bin/gnome-tweak-tool", line 47, in __init__
    model)
  File "/usr/lib/python2.7/site-packages/gtweak/tweakview.py", line 40, in __init__
    self._model.load_tweaks()
  File "/usr/lib/python2.7/site-packages/gtweak/tweakmodel.py", line 103, in load_tweaks
    mods = __import__("gtweak.tweaks", globals(), locals(), tweak_files, 0)
  File "/usr/lib/python2.7/site-packages/gtweak/tweaks/tweak_font.py", line 28, in <module>
    GSettingsRangeTweak("org.gnome.desktop.interface", "text-scaling-factor", adjustment_step=0.1, size_group=sg),
  File "/usr/lib/python2.7/site-packages/gtweak/widgets.py", line 94, in __init__
    _min, _max = self.settings.get_range(key_name)[1]
  File "/usr/lib64/python2.7/site-packages/gi/types.py", line 44, in function
    return info.invoke(*args)
NotImplementedError: structure type 'GVariant' is not supported yet