Add-On Check Button

(function() {

  if (window.__SSi != 'window0')
    return;

  CustomizableUI.createWidget({
    id: 'addons-update-button',
    defaultArea: CustomizableUI.AREA_NAVBAR,
    label: 'Add-ons-Update',
    tooltiptext: 'Add-ons-Update',
    onCommand: onCommand,
    onCreated: function(button) {
      button.style.listStyleImage = 'url(data:image/png;base64,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)';
    }
  });

  function onCommand(event) {

    let frameScript = function() {
      addEventListener('pageshow', function onPageshow(event) {
        let document = event.target;
        if (document.URL != 'about:addons')
          return;
        content.gViewController.doCommand('cmd_findAllUpdates');
        content.gViewController.doCommand('cmd_goToAvailableUpdates');
        removeEventListener('pageshow', onPageshow);
        let categories = document.getElementById('categories');
        let item = document.getElementById('category-availableUpdates');
        categories.addEventListener('mousedown', function onMousedown(event) {
          if (event.target != item) {
            item.hidden = true;
            categories.removeEventListener('mousedown', onMousedown);
          };
        });
      });
    };

    let frameScriptURI = 'data:,(' + frameScript.toString() + ')()';
    let window = event.target.ownerGlobal;
    window.openTrustedLinkIn('about:addons', 'tab');
    window.gBrowser.selectedBrowser.messageManager.loadFrameScript(frameScriptURI, true);

  };

})();