It's been a while since I last played DF and I'm surprised to see that both this article and the video are a bit light on details, IIRC they used to showcase upcoming updates a lot more.

Digging a bit more it looks like the magic system will be built around deities, spheres of influence [1], and workshops/professions centered around magic leading to procedurally generated spells. I'm really excited to see how it'll turn out.

[1] https://dwarffortresswiki.org/index.php/Sphere