Examine source code of Dark Mode Toggler

{
  "manifest_version": 2,
  "name": "Dark Mode Slider",
  "version": "1.0",
  "description": "Turn any webpage to dark mode using a slider",
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "browser_action": {
    "default_icon": "icon.png",
    "default_title": "Dark Mode Slider",
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{04df9dfa-80d1-4d38-8c4e-d44006276f88}"
    }
  }
}