Examine source code of BibleGateway Dark Mode

{
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "BibleGateway color settings"
  },
  "description": "BibGateway Dark Mode is a Firefox extension that adds a dark theme to BibGateway.com. Enjoy a more comfortable reading experience and reduced eye strain, perfect for long Bible study sessions, especially in low light environments",
  "manifest_version": 2,
  "name": "BibleGateway Dark Mode",
  "options_ui": {
    "page": "options.html",
    "browser_style": true
  },
  "version": "0.5",
  "permissions": [
    "storage",
    "tabs"
  ],
  "icons": {
    "16": "icon.png",
    "48": "icon.png",
    "128": "icon.png"
  },
  "content_scripts": [
    {
      "js": [
        "darkmode.js"
      ],
      "matches": [
        "https://www.biblegateway.com/*"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{a7ea6880-57c1-4f89-8282-b356df284bcc}"
    }
  }
}