Examine source code of Nudge

{
  "short_name": "Nudge",
  "name": "Nudge",
  "author": "Jacob Lurye",
  "description": "Redirect distracting webpages to the one you want to focus on.",
  "manifest_version": 2,
  "icons": {
    "128": "icon128.png"
  },
  "browser_action": {
    "default_popup": "index.html",
    "default_title": "Nudge"
  },
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "permissions": [
    "tabs",
    "storage"
  ],
  "version": "0.0.2resigned1",
  "browser_specific_settings": {
    "gecko": {
      "id": "nudge@example.org"
    }
  }
}