The idea that Fossil has as an SCM is that all your workflow ought to belong in the source repository; so, for example, the issue tracker that comes with Fossil stores all of its data inside of the same repo as the code. If you work on an issue and update it, the update travels with the code commits. If you raise an issue and push it to an upstream repo, everyone who syncs against it will see the issue, and so on and so forth.

Relevant discussion: https://www.reddit.com/r/linux/comments/914z8v/comment/e2yib...

I do find the homepage very complete and the documentation very understandable though, would recomend taking a look if you're interested.