Examine source code of Magma3 - Active Window

{
  "manifest_version": 3,
  "name": "Magma3 - Active Window",
  "version": "1.0.2",
  "permissions": [
    "tabs"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "magma3activewindows@magma3.com.br"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "type": "classic"
  },
  "action": {
    "default_icon": "icon.png"
  },
  "icons": {
    "128": "icon.png"
  }
}