@open_flags was not documented, and so:
jhbuild/checkout/gnome/gtk+-3/gtk/gtkplacessidebar.c:4743: Warning: Gtk:
incorrect number of parameters in comment block, parameter annotations
will be ignored.
/**
* GtkPlacesSidebar::show-starred-location:
* @sidebar: the object which received the signal.
+ * @open_flags: a single value from #GtkPlacesOpenFlags specifying how the
+ * starred file should be opened.
*
* The places sidebar emits this signal when it needs the calling
* application to present a way to show the starred files. In GNOME,