Since the original motivation from the OP was to understand maths in ML papers, has anyone tried the free Maths for ML book, https://mml-book.github.io/ https:/

Since the original motivation from the OP was to understand maths in ML papers, has anyone tried the free Maths for ML book, https://mml-book.github.io/ https://mml-book.github.io/, and if so what are your thoughts?