Examine source code of DragDrop-To-Do List

{
  "manifest_version": 2,
  "name": "Simple To-Do List",
  "version": "1.0",
  "description": "A simple to-do list extension for Firefox.",
  "icons": {
    "48": "icons/todo-48.png"
  },
  "browser_action": {
    "default_icon": {
      "48": "icons/todo-48.png"
    },
    "default_popup": "popup.html"
  },
  "permissions": [
    "storage"
  ],
  "web_accessible_resources": [
    "packages/Sortable.min.js"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{1363c81d-b9f5-4977-a091-c79aa20581b4}"
    }
  }
}