void
g_list_free_full (GList *list,
                  GDestroyNotify free_func);

Convenience method, which frees all the memory used
by a GList, and calls free_func on every element's
data.

https://developer.gnome.org/glib/stable/glib-Doubly-Linked-Lists.html#g-list-free-full

The ENTITY is expanded in i18n process, and legal.xml file
is never read.

Note that GTK+ sets a default title of _("About %s") on the dialog
window (where %s is replaced by the name of the application, but
in order to ensure proper translation of the title, applications
should set the title property explicitly when constructing a
GtkAboutDialog

https://developer.gnome.org/gtk3/stable/GtkAboutDialog.html