Examine source code of Style Switch

{
  "manifest_version": 2,
  "name": "Style Switch",
  "version": "0.3",
  "description": "Adds an icon to the address bar to enable / disable page style (CSS).",
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "59.0",
      "id": "{13b0d5e7-4f28-465b-8e26-33627f7012fe}"
    }
  },
  "icons": {
    "48": "icon.svg"
  },
  "permissions": [
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "page_action": {
    "browser_style": true,
    "default_icon": "enabled.svg",
    "default_title": "Style Switch",
    "show_matches": [
      "<all_urls>"
    ]
  },
  "commands": {
    "_execute_page_action": {}
  }
}