It will parse the document down to 5 levels of nested sections (`===== Section`).  Currently, any sections deeper than that will be lumped into the content of the kind 30041 events generated from fifth-level blocks.

In theory, we can go arbitrarily deep, but at a certain point, we don't need that much depth in an editor workflow that is driven by direct user input (versus a programmatic upload of something large and complex, like the Bible).  Setting a cutoff makes things a bit easier for both us and, IMO, for the end user.