Examine source code of FishtankRoomClicker

{
  "manifest_version": 2,
  "name": "FishTank Room Clicker",
  "version": "1.0",
  "description": "Switch cameras by clicking on doors",
  "permissions": [
    "activeTab",
    "storage"
  ],
  "browser_action": {
    "default_icon": "icon.png",
    "default_title": "FishTank Room Clicker"
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.fishtank.live/"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "icons": {
    "48": "icon.png",
    "128": "icon.png"
  },
  "applications": {
    "gecko": {
      "id": "ninjatest3215312@gmail.com",
      "strict_min_version": "53.0"
    }
  }
}