Examine source code of MouseHunt Dark Mode

{
  "name": "MouseHunt Dark Mode",
  "description": "Dark mode for MouseHunt's browser version",
  "version": "0.1.47",
  "manifest_version": 2,
  "permissions": [],
  "action": {
    "default_popup": "ui/popup.html",
    "default_icons": {
      "16": "assets/icon.png",
      "32": "assets/icon.png",
      "48": "assets/icon.png",
      "128": "assets/icon.png"
    }
  },
  "icons": {
    "16": "assets/icon.png",
    "32": "assets/icon.png",
    "48": "assets/icon.png",
    "128": "assets/icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.mousehuntgame.com/*"
      ],
      "css": [
        "css/main.css",
        "css/messagebox.css",
        "css/giftbox.css",
        "css/trap.css",
        "css/inbox.css",
        "css/team.css",
        "css/marketplace.css",
        "css/profile.css",
        "css/shop.css",
        "css/scoreboard.css",
        "css/inventory.css",
        "css/treasuremap.css",
        "css/camp/camp.css",
        "css/camp/journal.css",
        "css/camp/hud.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{a4cc589b-ede2-4cb2-a336-043a58b1c020}"
    }
  }
}