It looks like, finally, there is no reverse dep of this in the tree, hence, we should be able to treeclean it
Maybe I'm wrong, but I think this package is needed for some extra icons in GNOME 3 desktop. For example if you use the adwaita-icon-theme and have a downloaded .iso-file the correct icon is shown in nautilus when you have installed the gnome-icon-theme-extras package. Without gnome-icon-theme-extras there is no icon for .iso-files. So please don't remove this package.
Ah, right, it seems this was left as the place to put this icons... even if later it hasn't been updated :/ https://bugzilla.gnome.org/show_bug.cgi?id=330235#c9 https://bugzilla.gnome.org/show_bug.cgi?id=309324 Even the bugs are being handled upstream in "extras" component of adwaita-icon-theme but it seems it never got renamed as it wasn't updated I will need to unmask it. We could maybe pull it from some meta as, otherwise, most people will think that icons are not even existing :/
unmasked
Thank you very much :-)