Examine source code of Media URL Sniff

{
  "manifest_version": 2,
  "name": "Media URL Sniffer",
  "version": "1.0",
  "description": "Monitor and display streaming media URLs on the active tab.",
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "*://*/*"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "background": {
    "scripts": [
      "popup.js"
    ]
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{99b874dc-f439-4b94-b07d-ab4c975c2af1}"
    }
  }
}