title: is clipboard api removed from gtk4?
body: <p>During search the clipboard api in gnome. Only find clipboard api in gtk3. it seems that the clipboard api was removed from gtk4.</p>
  
  <p><a href="https://developer.gnome.org/gtk3/stable/gtkbase.html" rel="nofollow noreferrer">https://developer.gnome.org/gtk3/stable/gtkbase.html</a></p>
  
  <p><a href="https://developer.gnome.org/gtk4/stable/gtkbase.html" rel="nofollow noreferrer">https://developer.gnome.org/gtk4/stable/gtkbase.html</a></p>