Examine source code of DevBox

{
  "description" : "The Developer Toolbox",
  "name" : "DevBox",
  "manifest_version" : 2 ,
  "version" : "2.10.0",
  "icons" : {
    "16" : "app/icon-16x16.png",
    "48" : "app/icon-48x48.png",
    "128" : "app/icon-128x128.png"
  },
  "browser_action" : {
    "default_icon" : {
      "16" : "app/icon-16x16.png",
      "32" : "app/icon-32x32.png",
      "48" : "app/icon-48x48.png",
      "128" : "app/icon-128x128.png"
    }
  },
  "background" : {
    "scripts" : [
      "background.js" 
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{a3df6145-d8aa-44d4-af17-a740a940341c}"
    }
  }
}