Examine source code of NoPoW

{
  "manifest_version": 2,
  "name": "NoPoW",
  "version": "1.3",
  "description": "Removes annoying Proof-of-Work captchas by changing the user-agent.",
  "icons": {
    "48": "icons/border-48.png"
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [],
  "browser_specific_settings": {
    "gecko": {
      "id": "nopow@lexi.re"
    }
  }
}