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.
This seems more like a teaser trailer. I presume more information is forthcoming.
They have a history of at least trying to be transparent, especially in their Future of the Fortress posts[0]. Emphasize on trying to, as they're not exactly great at sticking to plans, though that certainly improved with the Kitfox partnership.
[0]: https://bay12games.com/dwarves/