Examine source code of Freediumizer

{
  "manifest_version": 2,
  "name": "Freediumizer",
  "version": "1.0.2",
  "description": "Automatically redirects member-only stories to Freedium.",
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "freediumizer.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{34c16148-0d03-455b-85d1-d524f3fde763}"
    }
  }
}