Solved! Go to Solution.
Esri-leaflet does not require any CDN. It's only dependency is Leaflet, which you could download and host directly on your own.
<!DOCTYPE html> <html> <head> <title></title> <meta http-equiv='content-type' content='text/html; charset=utf-8' /> <meta name='viewport' content='initial-scale=1.0 maximum-scale=1.0'> <link rel="stylesheet" href="vendor/Leaflet/dist/leaflet.css" /> <link rel="stylesheet" href="vendor/Leaflet.markercluster/dist/MarkerCluster.css" /> <link rel="stylesheet" href="vendor/Leaflet.markercluster/dist/MarkerCluster.Default.css" /> <link rel="stylesheet" href="vendor/leaflet-locatecontrol/src/L.Control.Locate.css" /> <link rel="stylesheet" href="css/styles.css" /> </head> <body> <script src="vendor/Leaflet/dist/leaflet-src.js"></script> <script src="vendor/Leaflet.markercluster/dist/leaflet.markercluster-src.js"></script> <script src="vendor/leaflet-locatecontrol/src/L.Control.Locate.js"></script> <script src="vendor/esri-leaflet/dist/esri-leaflet-src.js"></script> <script src="vendor/esri-leaflet/dist/extras/clustered-feature-layer-src.js"></script> <script src="bundle.js"></script> </body> </html>