You don't really know if it's repeating a certain device unless you follow this post about xbee everything. Everything Xbee
As far as this Sylvania plug. It's a repeater and your Hub will work out the mesh after you leave the hub off for more than 15 minutes. Once power up the hub your system will start healing the mesh. Whether your xiaomi devices using the plug for repeating is depending on what kind of mesh you have.
