Examine source code of Site Inspector

{
  "manifest_version": 2,
  "name": "Site Inspector",
  "version": "0.37",
  "description": "Provides an overview of website security and identity.",
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "purify.min.js",
        "content-script.js"
      ],
      "css": [
        "style.css"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "commands": {
    "shortcutz": {
      "suggested_key": {
        "default": "Ctrl+Alt+Y"
      },
      "description": "Send a 'toggle-feature' event"
    }
  },
  "permissions": [
    "webRequest",
    "<all_urls>",
    "webRequestBlocking",
    "storage"
  ],
  "web_accessible_resources": [
    "icons/*.svg"
  ],
  "browser_action": {
    "default_popup": "popup/popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{8d184e38-ae91-4bcb-a8c8-1f11b541c1e7}"
    }
  }
}