LearnChess was created by Sean B (chesswithsean) in 2015. Since then, four other people joined the project, although one did eventually leave the chess.com LearnChess group, and so no longer actively contributes to LearnChess. In the summer of 2016 LearnChess 1.0 was not working. The design was a disaster. The site was not mobile friendly and had a few other flaws. And so, the next design of LearnChess was made, and it still being adjusted.
First a contributor creates some sort of chess related content (puzzles for example) using chess.com) (or sometimes lichess), and posts it so that Chesswithsean) can code it onto LearnChess. Currently it's all added manually, meaning that not a lot of content can be added at once.