DEMOS
LDD and the extension of device's drain are the usual techniques to make higher breakdown voltage devices.
Usually a combination of both techniques are used to generate a "family of devices" with steped breakdown volgates.
Lower voltage ones have nothing about it, next level add the LDD and later levels use to extend more and more the drain until a total of, usually, no more than 4 to 5 different available devices. About the voltages values, it's process dependent.