I mean, they may not have as much as you want, but they do appear to have documentation.

https://wiki.freecad.org/

That has a manual in two ebook formats, PDF, and a French and Italian translation.

It has three help sections on the wiki, for each of users, power users, and developers.

And it apparently has some in-application help functionality.

And there’s a help forum.

EDIT: It also looks like some people have written books about using FreeCAD.