Examine source code of War Room Plus

{
  "manifest_version": 3,
  "name": "War Room Plus",
  "version": "1.3.1",
  "description": "Add bonus features to War Room!",
  "content_scripts": [
    {
      "js": [
        "js/darkmode.js"
      ],
      "css": [
        "css/darkmode.css"
      ],
      "matches": [
        "https://war.elk.sh/*"
      ]
    }
  ],
  "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": "christianbernier02@gmail.com",
      "strict_min_version": "42.0"
    }
  }
}