User Documentation
Well, there used to be documentation here, so what happened? Since Fluster includes it's own set of documentation embedded directly in the application, reflecting the state of the application at the time that it was built, keeping an extra set online was redundant, especially when that documentation couldn't use the components it was intending to document, at least not without significant added complexity.
You can access this documentation in the current version of Fluster via the command palette (cmd+p) or in the new Swift based version of Fluster, by using the special ? or ?? documentation syntax. If you're ever lost in the Swift based version of Fluster, just type Docs?? on a separate line, and Fluster will print out a list of further documentation commands to allow you to learn the app as you use it.