Initially to a PolyForm license[1], which I then forked to create my own[2]. I informally refer to it as an "edu source" license (the source available is primarily available for educational purposes).

[1]: https://polyformproject.org/licenses/strict/1.0.0/ (hn discussion: https://news.ycombinator.com/item?id=24804223)

[2]: https://github.com/LGUG2Z/komorebi-license