Examine source code of My Basic Extension

{
  "manifest_version" : 2 ,
  "name" : "My Basic Extension",
  "version" : "1.0",
  "description" : "A basic Firefox extension",
  "icons" : {
    "48" : "icon.png"
  },
  "permissions" : [
    "activeTab" 
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{407cdf8d-7ab8-48ff-9435-e216d3537531}"
    }
  }
}