Examine source code of Tab list

{
  "manifest_version": 2,
  "name": "Tab list",
  "description": "List and manage your open tabs",
  "icons": {
    "16": "icon-16.png",
    "48": "icon-48.png",
    "128": "icon-128.png"
  },
  "version": "1.0.1",
  "content_security_policy": "script-src 'self'; object-src 'self'; img-src chrome://favicon 'self' data:;",
  "browser_action": {
    "default_icon": "icon-48.png",
    "default_popup": "popup.html"
  },
  "permissions": [
    "tabs",
    "<all_urls>"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{03fff665-4215-4994-bf31-462d1563504b}"
    }
  }
}