There's a long list here: https://github.com/danistefanovic/build-your-own-x https://github.com/danistefanovic/build-your-own-x. Also, https://codecrafters.io/

There's a long list here: https://github.com/danistefanovic/build-your-own-x https://github.com/danistefanovic/build-your-own-x. Also, https://codecrafters.io/challenges/git https://codecrafters.io/challenges/git supports multiple languages (I'm the author). Many folks that try this challenge do it for the same reason you mentioned: to learn about a tool and learn a new language at the same time.