-> It's a map from page name to increasingly complex pagespec, although
-> the `optimize-depends` branch in my git repository changes that to a
-> map from a page name to a *list* of pagespecs which are automatically
-> or'd together for use (this at least means duplicates can be weeded out).
->
-> See [[todo/should_optimise_pagespecs]] for more on that.
+> Nowadays, it's a hash of pagespecs, and there
+> is also a `IkiWiki::depends_simple` hash of simple page names.