Hi Joe
It could be expressed better! It’s a very typical piece of Jeremy-documentation: all the information is there, but expressed so concisely as to be nearly incomprehensible… It mixes up explaining how the feature works with how to use it, and frequently assumes the reader can infer the latter from the former...
Anyhow, the blue light bulb is telling you what parameter value to use to match that used by the core. (The subtext here being that you can use the tm-fold-all-tiddlers message in custom situations to fold something other than the story river).
The warning triangle is pointing out that not setting the foldStatePrefix parameter can lead to data loss.
I’ve made some updates to the docs, and changed the underlying code so that a default is safely applied.
Best wishes
Jeremy.