Examine source code of Speed Zoom

{
  "manifest_version": 2,
  "name": "Speed Zoom",
  "version": "1.0",
  "description": "Set page zoom to preset levels with a single click.",
  "permissions": [
    "activeTab",
    "tabs"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Zoom",
    "default_icon": {
      "32": "sz_icon_32.png",
      "64": "sz_icon_64.png",
      "128": "sz_icon_128.png"
    }
  },
  "icons": {
    "32": "sz_icon_32.png",
    "64": "sz_icon_64.png",
    "128": "sz_icon_128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "speed.zoom.ext@protonmail.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "strict_min_version": "142.0"
    }
  }
}