Examine source code of LeetPeek

{
  "manifest_version": 2,
  "name": "LeetPeek",
  "version": "1.1",
  "description": "Displays stats for saved LeetCode usernames.",
  "permissions": [
    "storage",
    "tabs",
    "https://leetcode.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon_16.png",
      "32": "icons/icon_32.png",
      "48": "icons/icon_48.png",
      "128": "icons/icon_128.png"
    }
  },
  "icons": {
    "16": "icons/icon_16.png",
    "32": "icons/icon_32.png",
    "48": "icons/icon_48.png",
    "128": "icons/icon_128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{5b1252e3-396c-4764-899b-c90d9502ed06}"
    }
  }
}