The UL is a certification program, They can't really tell you what you can/can't install in your own home. They can't even tell you what you can/can't sell to someone else. The issue is that most distributors won't buy/sell things w/o UL approval (for good reason). I'd most certainly guess that the creators have had them in their home for some time.

When I worked in commercial electronics, it was very typical for engineers to install development products in their home, long before UL approval.