this is of mapbox.js locations.html example that I showed to mike and david and also used for measuring performance when comparing mapbox-gl vs mapbox.js for cpl 2020, april

<!DOCTYPE html>

 <html class="no-js"> 
    <head>
        <meta charset="utf-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <title></title>
        <meta name="description" content="">
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <link rel="stylesheet" href="https://api.mapbox.com/mapbox.js/v3.1.1/mapbox.css">
        <script src="https://api.mapbox.com/mapbox.js/v3.1.1/mapbox.js"></script>

L.mapbox.accessToken = 'pk.eyJ1Ijoic2tvcmFzYXVydXMiLCJhIjoiY2pmNDNpYXBuMGl3cjJ3bzF6cm1kbHFxaSJ9.5fsBdDBA9bm_mO2idlMP9A';
// https://c.tile.openstreetmap.org/16/17923/24475.png

var myLayer = 'https://api.mapbox.com/styles/v1/skorasaurus/ck2ew6z291ct01cnmjc5lz50b/tiles/256/{z}/{x}/{y}@2x?access_token=pk.eyJ1Ijoic2tvcmFzYXVydXMiLCJhIjoiaEdGTUZWTSJ9.osOC8tWU3bMaNprVNoEu7g';

var myMap = L.map('mapid').setView([41.51783221717116, -81.68334960937501], 11);
L.tileLayer(myLayer, {attribution: '<a href="https://www.mapbox.com/about/maps/" target="_blank">© Mapbox</a>, <a href="https://www.openstreetmap.org/">© OpenStreetMap</a>'}).addTo(myMap);

// for locations.html only
//var featLayer = L.mapbox.featureLayer().loadURL('js/locations-points.geojson').addTo(mymap); 
// FOR LOCAL.wordpress.test // neither work on temp.cpl.org
var featLayer = L.mapbox.featureLayer().loadURL('locations-points.geojson').addTo(myMap);

featLayer.on('ready', function() {
    featLayer.eachLayer(function(tehLayer) {
    	 popupContent = '<a href="'+tehLayer.feature.properties.shortlink+'">'+tehLayer.feature.properties.name +'</a><br>' + tehLayer.feature.properties.housenumber + ' ' + tehLayer.feature.properties.street+ '<br>' + 
	    '<a href="https://www.google.com/maps/search/'+tehLayer.feature.properties.housenumber + ' ' + tehLayer.feature.properties.street+ " Cleveland" + ' ' + tehLayer.feature.properties.postcode + '">'+' Get directions </a>'; 
		 
		tehLayer.bindPopup(popupContent);
    });
}).addTo(myMap);        
        </script>

</body>
</html>

https://api.mapbox.com/mapbox.js/v3.1.1/mapbox.js