Examine source code of SecurePass Meter

{
  "manifest_version": 2,
  "name": "SecurePass Meter",
  "version": "1.0",
  "description": "Check the strength of your password easily.",
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icons/icon48.png"
  },
  "background": {
    "scripts": []
  },
  "applications": {
    "gecko": {
      "id": "SecurePassMeter@mysteriousimmature.com",
      "strict_min_version": "80.0"
    }
  }
}