Examine source code of iFrame remover

{
  "manifest_version": 2,
  "applications": {
    "gecko": {
      "id": "walkingice@web_extension_remove_iframe"
    }
  },
  "name": "iFrame remover",
  "version": "0.2resigned1",
  "description": "Remove iFrame in current page",
  "icons": {
    "100": "imgs/logo.png"
  },
  "background": {
    "scripts": [
      "js/background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "32": "imgs/browserAction_32.png"
    },
    "default_popup": "popup/popup.html",
    "default_title": "remove iframes"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "js/main.js"
      ],
      "run_at": "document_start"
    }
  ],
  "commands": {
    "shortcut_rm_iframes": {
      "suggested_key": {
        "default": "Alt+Shift+I"
      },
      "description": "Send a 'toggle-feature' event"
    }
  },
  "options_ui": {
    "page": "options/options.html"
  },
  "permissions": [
    "tabs",
    "activeTab",
    "storage"
  ]
}