Examine source code of Kaomoji Picker

{
  "manifest_version": 2,
  "name": "kaomoji-panel",
  "version": "1.1.1",
  "description": "A kaomoji picker, ٩(◕‿◕｡)۶",
  "icons": {
    "48": "icon-48.png",
    "128": "icon-128.png"
  },
  "browser_action": {
    "default_title": "Kaomoji Picker",
    "default_popup": "index.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{38f55b06-e3c2-46ee-ac06-9186ab2dc565}"
    }
  }
}