Examine source code of Color Picker

{
  "name": "Flat Color Extension",
  "manifest_version": 2,
  "version": "2.1resigned1",
  "description": "The best colours in one click",
  "browser_action": {
    "default_popup": "app.html",
    "default_icon": "img/icon.png"
  },
  "permissions": [
    "clipboardWrite"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{ef01d286-06bf-4a57-a5e4-a163c01f23bc}"
    }
  }
}