Examine source code of Jumper

{
  "manifest_version": 2,
  "name": "Jumper",
  "version": "1.0.0",
  "browser_action": {
    "default_icon": {
      "32": "assets/icon32.png"
    },
    "default_title": "Platformer",
    "default_popup": "popup.html"
  },
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{91052258-c26e-4d4d-8880-d211e584ef73}"
    }
  }
}