def Gtk.TextBuffer.register_serialize_tagset(tagset_name)

This function registers GTK+'s internal rich text serialization format with the passed @buffer. The internal format does not comply to any standard rich text format and only works between GtkTextBuffer instances. It is capable of serializing all of a text buffer's tags and embedded pixbufs. This function is just a wrapper around gtk_text_buffer_register_serialize_format(). The mime type used for registering is "application/x-gtk-text-buffer-rich-text", or "application/x-gtk-text-buffer-rich-text;format=@tagset_name" if a The @tagset_name can be used to restrict the transfer of rich text to buffers with compatible sets of tags, in order to avoid unknown tags from being pasted. It is probably the common case to pass an identifier != %NULL here, since the %NULL tagset requires the receiving buffer to deal with with pasting of arbitrary tags. newly registered format's mime-type.