Examine source code of Search JustWatch

{
  "manifest_version": 2,
  "name": "Search JustWatch",
  "version": "1.0",
  "description": "Search JustWatch.com/tr for any highlighted text.",
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "activeTab",
    "contextMenus"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f970a9fc-a283-4151-ae04-a097a0f440d5}"
    }
  }
}