"toolbars": {
    "viewer": ["exampleButton", "exampleVBSButton"],

Button with JS example

The labeling is defined under "buttons":

 "buttons": {
      "exampleButton": {
        "type": "JS",
        "name": {
          "de-DE": "JS Beispiel",
          "en-GB": "JS Example"
        },
        "callback": "onExampleButtonClicked",
        "icon": "images/bell-solid.svg",
        "tooltip": {
          "de-DE": "JS Beispiel",
          "en-GB": "JS Example"
        }
      },
      "exampleVBSButton": {
        "type": "VBS",
        "icon": "images/bell-solid.svg",
        "name": {
          "de-DE": "VBS Beispiel",
          "en-GB": "VBS Example"
        },
        "script": "/plugins/vbb/wstest.vbs",
        "requestFromPdm": "currentuser",
        "tooltip": {
          "de-DE": "VBS Beispiel",
          "en-GB": "VBS Example"
        }
      },