They say: "...it is a condition of access to our API documentation that you do not use it to develop or distribute any bridges or devices which interpret the h

They say: "...it is a condition of access to our API documentation that you do not use it to develop or distribute any bridges or devices which interpret the hue API in order to control physical devices." A lightbulb is a physical device. It seems clear to me that they distribute this API and documentation with a license that ensures that you can only write software to work with their hardware.