anchor.diff:  
       final enableRobots = hasExperimentalCookie ||
           (!activeConfiguration.blockRobots && isProductionHost);
  -    final uiCacheEnabled = isProductionHost;
  +    final uiCacheEnabled = isPrimaryHost && !hasExperimentalCookie;
   
       registerRequestContext(RequestContext(
         isExperimental: isExperimental,
  
positive.code: import 'configuration.dart';
  import 'handlers.dart';
  import 'markdown.dart';
  import 'utils.dart' show fileAnIssueContent, parseCookieHeader;
  
  const _hstsDuration = Duration(minutes: 15);
  
negative.code: shelf.Handler _requestContextWrapper(shelf.Handler handler) {
    return (shelf.Request request) async {
      final host = request.requestedUri.host;
      final isPrimaryHost = host == urls.primaryHost;
      final isProductionHost = activeConfiguration.productionHosts.contains(host);
      final isPubDev = host == 'pub.dev';
  
  