docs: def _getAppStoreResource(self, ctx, name):
          """
          Customize child lookup such that all installed offerings on the site
          store that this page is viewing are given an opportunity to display
          their own page.
          """
          offer = self.frontPageItem.store.findFirst(
              offering.InstalledOffering,
              offering.InstalledOffering.offeringName == unicode(name, 'ascii'))
          if offer is not None:
              pp = ixmantissa.IPublicPage(offer.application, None)
              if pp is not None:
                  warn("Use the sharing system to provide public pages,"
                       " not IPublicPage",
                       category=DeprecationWarning,
                       stacklevel=2)
                  return pp.getResource()
              return SharingIndex(offer.application.open(),
                                  self.webViewer)
          return None