Examine source code of sample-extension

{
  "manifest_version": 2,
  "name": "sample-extension",
  "version": "1.0",
  "description": "Sample extension",
  "browser_specific_settings": {
    "gecko": {
      "id": "sample@mock.com"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "communicate.js"
      ],
      "run_at": "document_start"
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "nativeMessaging",
    "nativeMessagingFromContent",
    "geckoViewAddons",
    "webRequest",
    "cookies",
    "webRequestBlocking",
    "tabs",
    "webNavigation",
    "<all_urls>"
  ]
}