Steve Kirby came to me to show me a limb rig that was made of two controllers and one shape layer. It was a really complicated setup that he had been copy/pasting into his own projects to speed up his workflow. He thought that if it could be turned into a script with additional functionality, it could be a great product for the community.
I worked on the scripting side while he continued to refine his rig to perform faster and do more things. We ended up with three different base limb rigs. I would take his rigs and convert them into JSX code with CompCode, another tool by renderTom, and plug it into a framework I had built, allowing the creation of FK and joint controllers, swapping base limb types, and copy/pasting custom limb configurations.
It's performed very well so far, and we continue to develop it further. Steve also created all of the documentation, marketing, and tutorial materials, which are excellently done and a TON of work.
Check it out on aescripts + aeplugins