Examine source code of disqus-undirect

{
  "manifest_version": 2,
  "name": "disqus-undirect",
  "version": "0.2.2resigned1",
  "description": "Redirect disq.us links without requesting.",
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "permissions": [
    "*://disqus.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://disqus.com/*"
      ],
      "js": [
        "undirect.js"
      ],
      "run_at": "document_end",
      "all_frames": true
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{58a91034-688c-4104-b2d3-04d086882925}"
    }
  }
}