Examine source code of Dark Mode Lite

{
  "manifest_version": 3,
  "name": "Dark Mode Lite",
  "description": "A lightweight dark mode",
  "version": "3.0.0",
  "commands": {
    "keyboard-toggle-dark-mode": {
      "suggested_key": {
        "windows": "Ctrl+Shift+K",
        "mac": "Command+Shift+K",
        "chromeos": "Ctrl+Shift+K",
        "linux": "Ctrl+Shift+K"
      },
      "description": "Toggle Dark Mode"
    }
  },
  "permissions": [
    "storage",
    "tabs"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "vendor/browser-polyfill.min.js",
        "contentScripts/main.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    }
  ],
  "background": {
    "scripts": [
      "background/main.js"
    ]
  },
  "action": {
    "default_icon": {
      "96": "icons/icon_96.png"
    },
    "default_title": "Toggle Dark Mode"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{e8416bca-acfd-4c45-8f57-b6961948b175}"
    }
  }
}