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}"
    }
  }
}