Examine source code of UltimaDark forked

{
  "manifest_version": 2,
  "name": "UltimaDark forked",
  "version": "1.6.66.74",
  "description": "The extension uses agressive techniques to get a dark mode everywhere on internet\nThis is the forked version for faster and better",
  "icons": {
    "48": "icons/48.png",
    "96": "icons/2x.png"
  },
  "content_security_policy": "script-src 'self' blob: 'unsafe-eval' 'sha256-RooFZFVBc+eqIlPYtIwvNYqUBaN1qp1VnXMy2xZLRKg='; ",
  "commands": {
    "toggle-site": {
      "suggested_key": {
        "default": "Ctrl+Shift+U",
        "mac": "Ctrl+Shift+U"
      },
      "description": "Toggles UltimaDark on the current site"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "136.0",
      "id": "{b2753dde-3be2-4b77-9a90-0f9a57b8b26e}"
    },
    "gecko_android": {
      "strict_min_version": "136.0"
    }
  },
  "permissions": [
    "<all_urls>",
    "tabs",
    "webNavigation",
    "webRequest",
    "webRequestBlocking",
    "storage",
    "unlimitedStorage"
  ],
  "browser_action": {
    "default_icon": "icons/38.png",
    "default_title": "UltimaDark forked",
    "default_popup": "popup/popup.html?mode=uDark-popup"
  },
  "background": {
    "scripts": [
      "fakeContentScriptClass.js",
      "backgroundClass.js",
      "Listeners.js",
      "background.js",
      "uDarkEncoder.js"
    ]
  },
  "devtools_page": "devtools/devtools.html"
}