Examine source code of Awesome Timestamp

{
  "description": "Convert timestamps to datetime and datetime to timestamps.",
  "manifest_version": 2,
  "name": "Awesome Timestamp",
  "version": "1.4.3resigned1",
  "homepage_url": "http://www.webit-service.de",
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "browser_action": {
    "default_icon": "icons/icon-48.png",
    "default_title": "Awesome Timestamp",
    "default_popup": "popup/index.html"
  },
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "jid1-c90bOQBeh1Y0tQ@jetpack"
    }
  }
}