function drawDeelgebieden(map, eventId) {
    let params = ''
    const cacheToken = sessionStorage.getItem('jotihunt.kmlCache')
    if (cacheToken) {
        params = '?cb=' + cacheToken
    }

    const kmlUrl = window.location.origin + '/deelgebieden-kml/' + eventId + params
    console.log("Using kmlUrl: " + kmlUrl);
    const kmlOptions = {
        suppressInfoWindows: false,
        preserveViewport: false,
        map: map
    };

    return new google.maps.KmlLayer(kmlUrl, kmlOptions);
}
@@ -53,16 +53,30 @@
 rams = '
+?event=2022-01
 '%0A    co
@@ -173,20 +173,21 @@
  params 
++
 = '
-?
+&
 cb=' + c
@@ -508,8 +508,9 @@
 ions);%0A%7D
+%0A

Update map_deelgebieden.js