Comment # 7 on bug 1057976 from Wolfgang Bauer

These packages are recommended by libgtk-3-0 itself:
$ rpm -q --recommends libgtk-3-0 
gtk3-branding
gtk3-immodule-amharic = 3.20.10
gtk3-immodule-inuktitut = 3.20.10
gtk3-immodule-thai = 3.20.10
gtk3-immodule-tigrigna = 3.20.10
gtk3-immodule-vietnamese = 3.20.10
gtk3-lang
gvfs

(that's on 42.3, but should be similar on 42.2)