This exposes the base so that we can reimplement StClipboard on top. Some gtk-docs have been added for documentation and introspection purposes. https://gitlab.gnome.org/GNOME/mutter/merge_requests/320
This is a simple implementation of a MetaSelectionSource, able to hold a single mimetype, provided as GBytes. https://gitlab.gnome.org/GNOME/mutter/merge_requests/320