Examine source code of Theme Toggle

{
  "manifest_version": 2,
  "name": "Theme Toggle",
  "version": "1.0",
  "description": "Toggle Firefox's color scheme between Light and Dark.",
  "author": "tommyrot",
  "homepage_url": "https://github.com/tommyrot/themetoggle",
  "browser_specific_settings": {
    "gecko": {
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      },
      "id": "{28fe7f8d-727b-4c1a-85cb-6a2ffebb2fec}"
    }
  },
  "permissions": [
    "browserSettings",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icon.svg",
    "default_title": "Toggle Light/Dark Theme"
  },
  "icons": {
    "48": "icon.svg"
  }
}