Examine source code of Task List Manager

{
  "manifest_version": 2,
  "name": "Task List Manager",
  "version": "1.0",
  "description": "Manage your tasks easily",
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icon.png"
    }
  },
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{b5445535-d85c-4015-a98e-b838462c8408}"
    }
  }
}