Examine source code of Post Request Sniffer

{
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "content_script.js"
      ]
    }
  ],
  "description": "exposes post requests , e.g. to https://postpen.requestcatcher.com/",
  "applications": {
    "gecko": {
      "id": "postpen@jochnickel.github.com"
    }
  },
  "icons": {
    "48": "icons/border-48.png"
  },
  "manifest_version": 2,
  "name": "Post Request Sniffer",
  "options_ui": {
    "page": "options.html"
  },
  "permissions": [
    "storage",
    "webRequest",
    "webRequestBlocking",
    "<all_urls>"
  ],
  "version": "1.4"
}