Examine source code of doki-doki-leetcode

{
  "manifest_version": 2,
  "name": "Doki-LC",
  "author": "Brian Mai",
  "version": "1.0",
  "description": "LeetCode editor image overlay.",
  "icons": {
    "48": "icon-48.png"
  },
  "browser_action": {
    "default_popup": "doki.html",
    "default_icon": "icon-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://leetcode.com/problems/*"
      ],
      "js": [
        "overlay.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "doki.png"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "@doki-doki-leetcode",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "storage",
    "activeTab",
    "tabs"
  ]
}