This Bill was passed in September of 2015. It allows tiny homes to be used for some types of occupancy, while not requiring the same level of complexity as traditional homebuilding or development standards. For example, building officials are able to use codes that they already know and understand, so it makes it simpler for them to design plans with Appendix Q.
Appendix Q is an addition to the International Building Code (IBC) that was added in 2018. Appendix Q states do not specifically mention Tiny Houses, they apply to accessory dwelling units (ADU), which may include tiny houses in some situations.