I'm interested in learning to program with expl3. While the documentation is well written - kudos to those who wrote it, must have been a major effort - it does not contain many code examples. Like probably most of us, I find that looking at examples greatly helps when getting into a new language or paradigm.
Are there some already released, useful packages out there that illustrate how to use expl3 style key processing, flow control, data structures etc. to solve some real world document formatting tasks?