Examine source code of PoE Overlay: Dash

{
  "name": "PoE Overlay: Dash",
  "description": "Share your current session on pathofexile.com with PoE Overlay",
  "version": "0.0.0.3",
  "manifest_version": 2,
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "permissions": [
    "cookies",
    "*://*.pathofexile.com/*",
    "*://*.daum.net/*",
    "*://web.poe.garena.tw/*"
  ],
  "browser_action": {
    "default_title": "Dash Session"
  },
  "icons": {
    "16": "/images/icon_16.png",
    "32": "/images/icon_32.png",
    "48": "/images/icon_48.png",
    "128": "/images/icon_128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{bd6b06e1-7e2e-49fe-9081-7e69ac7926e2}"
    }
  }
}