[SuperZen]

// my.json
// [30.60000, 50.470000]

<script>
  fetch('my.json').then(r => r.json()).then(myJson => {
    mapboxgl.accessToken = 'pk.eyJ1IjoiYWx0Y3RybCIsIm';
    var map = new mapboxgl.Map({
    container: 'map',
    style: 'mapbox://styles/mapbox/streets-v11',
    center: myJson, // <-----------------
    zoom: 12
    });

    // Create a default Marker and add it to the map.
    var marker1 = new mapboxgl.Marker({ color: 'red'})
    .setLngLat([30.60000, 50.470000]) // <-----------------
    .addTo(map);

  });
</script>