Examine source code of td-debugger

{
  "description": "Treasure Data TD-JS-SDK debugger for Firefox",
  "manifest_version": 2,
  "name": "td-debugger",
  "version": "1.0",
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "*://*/*/",
    "tabs"
  ],
  "icons": {
    "48": "td-icon.jpg"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ]
}