Examine source code of Onion-Location Detector

{
  "manifest_version": 2,
  "name": "Onion-Location Detector",
  "version": "1.3",
  "description": "Detects Onion-Location header and meta tag, changes icon accordingly",
  "permissions": [
    "webRequest",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/default-16.png",
      "32": "icons/default-32.png"
    }
  },
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{93f98ccd-084e-48d7-9c1f-1b7db6d857a4}"
    }
  }
}