As you know, documentation is always incomplete.
Feel free to help yourself and others by contributing to it.
Just edit the pages on pmwiki.org.
You might want to follow or contribute to the documentation guidelines.
PmWiki versions 2.3.x have a function which can highlight the syntax of the markup language and make the documentation easier to read. See $EnablePmSyntax if you want to enable it.
Categories - Categories are a way to organize and find related pages
Page lists - Searching and listing pages by multiple criteria with templated output
Attach lists - Get a list of files uploaded and attached to a group using (:attachlist:) (Directives to specify page titles, descriptions, keywords, and display)