[kisonecat]

The HN community might be interested in the XML-based tech used to produce this book, namely https://pretextbook.org/

[wiktor-k]

Sadly the "source on github" links are broken on https://pretextbook.org/examples.html

[yawboakye]

https://github.com/PreTeXtBook/pretext

[scythmic_waves]

In fact, I came to the comments to ask. Thank you!