This is not “now includes.” This has been going on for many years. The resistor reduces the “driving current” of a magnesium anode to that of aluminum. The hope is to keep a water heater from failing under warranty in “aggressive” water, meaning that which consumes anodes rapidly. Sure it works, but our feeling is that it’s not such a great thing. We’re more interested in making water heaters last longer than making anodes last longer.