Examine source code of Nocturne Dark Mode

{
  "manifest_version": 3,
  "name": "Nocturne Dark Mode",
  "version": "1.3.0",
  "description": "Dark mode for every site. Uses a site's own dark theme when it has one, so pages look right instead of inverted. No white flash.",
  "permissions": [
    "storage",
    "alarms",
    "scripting"
  ],
  "optional_host_permissions": [
    "<all_urls>"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "run_at": "document_start",
      "all_frames": true,
      "match_about_blank": true,
      "css": [
        "content/guard.css"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "action": {
    "default_title": "Nocturne",
    "default_popup": "popup/popup.html",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    }
  },
  "options_ui": {
    "page": "options/options.html",
    "open_in_tab": true
  },
  "commands": {
    "toggle-site": {
      "suggested_key": {
        "default": "Alt+Shift+D"
      },
      "description": "Turn Nocturne on or off for this site"
    },
    "toggle-global": {
      "suggested_key": {
        "default": "Alt+Shift+N"
      },
      "description": "Turn Nocturne on or off everywhere"
    }
  },
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png",
    "128": "icons/icon-128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "nocturne@tiltedlunar.github.io",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}