Adds the general page meta data support, and a small input box
below every page, which allows users to add arbitrary invisible
infos about the current page. The data will be stored into the
page hash as $data["meta"]["meta"] entry (four levels deep
All that meta data information must however be evaluated by other
specialized plugins later to make sense:
prev << "module/tour"
next >> "meta/builtincategories"

You cannot modify the README.plugins file, but anyhow any ideas or suggestion should as usually get filed on BugReports, UserSuggestions or even better the README.plugins.Discussion.