+only use exported symbols should not be broken by future ikiwiki changes.
+
+## Most often used functions, by number of calls from plugin code
+
+ 27 IkiWiki::possibly_foolish_untaint
+
+Not very happy about exporting, it's not ikiwiki-specific,
+and plugins that need to untaint things should think about it, hard.
+
+ 12 IkiWiki::userinfo_get
+ 5 IkiWiki::userinfo_set
+
+Used by only 4 plugins, all of which are fairly core, so thinking
+don't export.
+
+ 11 IkiWiki::preprocess
+ 8 IkiWiki::filter
+ 4 IkiWiki::linkify
+ 4 IkiWiki::htmlize
+
+The page rendering chain. Note that it's very common to call `preprocess(filter(text))`,
+or `htmlize(linkify(preprocess(filter(text))))`, while `htmlize(linkify(preprocess(text))`
+is called less frequently, and it's also not unheard of to leave out a step and do
+`htmlize(preprocess(text))`. (I haven't checked if any of those cases are bugs.)
+
+It would be nice if the api could avoid exposing the details of the render chain,
+by providing a way to say "I have filtered text, and would like html", or "I have raw
+text and would like to get it up to the preprocess stage".
+
+Another problimatic thing is plugins often define functions named 'preprocess', etc.
+
+ 12 IkiWiki::linkpage
+ 11 IkiWiki::pagetitle
+ 6 IkiWiki::titlepage
+
+These go together; linkpage is needed by all link plugins, and the others are used widely.
+All should be exported.
+
+ 7 IkiWiki::saveindex
+ 5 IkiWiki::loadindex
+
+Still too internal to ever be exported?
+
+ 7 IkiWiki::redirect
+
+Only used by 4 plugins, and not in IkiWiki.pm itself, so probably not to be exported.
+
+ 7 IkiWiki::dirname
+ 4 IkiWiki::basename
+
+Not ikiwiki-specific, don't export.
+
+ 6 IkiWiki::refresh
+
+Very internal, not part of IkiWiki.pm, don't export.
+
+ 5 IkiWiki::yesno
+
+Not ikiwiki-specific, but worth exporting to get a consistent localised yes/no parser
+for directives.
+
+ 5 IkiWiki::showform
+ 4 IkiWiki::decode_form_utf8
+
+Only used by 3 fairly core plugins, not in IkiWiki.pm, don't export.
+
+ 5 IkiWiki::rcs_update
+ 4 IkiWiki::rcs_prepedit
+ 5 IkiWiki::is_admin
+ 5 IkiWiki::cgi_savesession
+ 4 IkiWiki::cgiurl
+
+Not enough use, I think, to export.
+
+ 5 IkiWiki::enable_commit_hook
+ 5 IkiWiki::disable_commit_hook
+
+Deep internal magic, if exported people will use it wrong, only used by core plugins.
+
+ 4 IkiWiki::check_canedit
+
+Probably needs to evolve more and be more widely used before being exported.
+
+## Variables used by plugins but not exported yet
+
+* %IkiWiki::pagecase (aggregate)
+* %IkiWiki::backlinks (pagestats)