anchor.diff:  
         proxy_connect_timeout 20s;
   
  -      proxy_next_upstream_tries 3;
  -      proxy_next_upstream error timeout http_502 http_404;
  +      proxy_next_upstream_tries 2;
   
         # Replace host header.
         proxy_set_header Host 'tile.openstreetmap.org';
  
positive.code:       proxy_cache_revalidate on;
        proxy_cache_min_uses 4;
  
        add_header x-cache-status $upstream_cache_status;
  <% else %>
        # Severely rate limit Browser UAs which are not sending a referer.
        # With no referer we do not know who is using tiles
  
negative.code: }
  
  # Limit Cache-Control header to only approved User-Agents
  map $tile_cache$osm_referer$http_user_agent $limit_http_cache_control {
    default '';                             # Unset Header
    '~^clientosmMozilla\/5\.0\ \(X11'       $http_cache_control; # Pass Header
    '~^clientosmMozilla\/5\.0\ \(Windows'   $http_cache_control; # Pass Header
    '~^clientosmMozilla\/5\.0\ \(iPhone'    $http_cache_control; # Pass Header
    '~^clientosmMozilla\/5\.0\ \(Macintosh' $http_cache_control; # Pass Header
    '~^clientosmMozilla\/5\.0\ \(Linux'     $http_cache_control; # Pass Header
  }
  
  # Limit Pragma header to only approved User-Agents
  map $tile_cache$osm_referer$http_user_agent $limit_http_pragma {
    default '';                             # Unset Header
    '~^clientosmMozilla\/5\.0\ \(X11'       $http_pragma; # Pass Header
    '~^clientosmMozilla\/5\.0\ \(Windows'   $http_pragma; # Pass Header
    '~^clientosmMozilla\/5\.0\ \(iPhone'    $http_pragma; # Pass Header
    '~^clientosmMozilla\/5\.0\ \(Macintosh' $http_pragma; # Pass Header
    '~^clientosmMozilla\/5\.0\ \(Linux'     $http_pragma; # Pass Header
  }
  
  # Find Browser User-Agents which are not sending a referer.
  # Browsers with no referer could be due to Browser extension or website Referrer-Policy
  map $tile_cache$http_referer$scheme$http_user_agent $deny_missing_referer {
    default                                   0; # Not denied
    '~^clienthttpsMozilla\/5\.0\ \(X11'       1;
    '~^clienthttpsMozilla\/5\.0\ \(Windows'   1;
    '~^clienthttpsMozilla\/5\.0\ \(iPhone'    1;
  