Add a button on top of navigationbar

Dear All,

what is the simplest way to add a button on top of navigation bar similar to what we have in the demo projects where exist a button to download the entire project?
Like here for example?
https://demo.lizmap.com/lizmap/index.php/view/map?repository=javascript&project=lampadaires

Thanks
Pierluigi

The easier way is probably to use Lizmap Javascript events and classic JS.

lizMap.events.on({
    'uicreated': function () {
        const button = document.createElement("button");
        button.textContent = "Lizmap Rocks!";
        button.style.position = "absolute";
        button.style.top = "100px";
        button.style.right = "100px";
        button.style.zIndex = 2000;
        document.body.appendChild(button);        
    }
});

Result :