[pmwiki-users] Site vs $SiteGroup

[romat2]

I am now confused by usage of $SiteGroup. Should it be supported
everywhere? Currently, it is not accepted in XLPage() call in
config.php. I also wonder why it is used both in XLPageTemplate
(http://www.pmwiki.org/wiki/PmWiki/XLPageTemplate)

  '{$SiteGroup}.EditQuickReference' => '',
  '{$SiteGroup}.UploadQuickReference' => '',
  'Site/Search' => '',
  'Site/AllRecentChanges' => '',

Roman