Remove OSM Black & White layer which is no longer in service

public_html/layers.js

@@ -47,16 +47,6 @@ function createBaseLayers() {
                 type: 'base',
         }));
 
-        world.push(new ol.layer.Tile({
-                source: new ol.source.XYZ({
-			"url" : "http://tiles.wmflabs.org/bw-mapnik/{z}/{x}/{y}.png",
-			"attributions" : "© <a href=\"https://www.openstreetmap.org/copyright\" target=\"_blank\">OpenStreetMap</a>  contributors."
-                }),
-                name: 'osm_blackwhite',
-                title: 'OSM Black and White',
-                type: 'base',
-        }));
-
         world.push(new ol.layer.Tile({
                 source: new ol.source.OSM({
                         "url" : "https://{a-z}.basemaps.cartocdn.com/dark_all/{z}/{x}/{y}.png",