Examine source code of HTTP Status Code

{
  "manifest_version": 2,
  "name": "HTTP Status Code",
  "description": "Shows HTTP response status code as a badge icon.",
  "version": "1.2.1resigned1",
  "homepage_url": "https://github.com/amad/firefox-status-code",
  "icons": {
    "48": "icon.svg",
    "96": "icon.svg"
  },
  "browser_action": {
    "default_icon": {
      "16": "icon.svg",
      "32": "icon.svg"
    }
  },
  "permissions": [
    "<all_urls>",
    "tabs",
    "webNavigation",
    "webRequest"
  ],
  "background": {
    "scripts": [
      "index.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "all_frames": true,
      "run_at": "document_start"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{631f0d87-7b05-4ef7-8c28-70dd22c32e62}"
    }
  }
}