Side by side MultiPath TCP and Kernel-DBus in one package.
With updated MPTCP support mptcp-sources-3.12-r2 also came new USE flag kdbus, which will allow you compile in kdbus (Drivers -> CONFIG_KDBUS)
For testing kdbus, you’ll need systemd with kdbus USE.
WARNING: For important machines just leave kdbus disabled. It may work, but it’s not tested enough for production.