Examine source code of Idle - Simples Examples

{
  "name": "Idle - Simples Examples",
  "version": "2.0.4",
  "description": "Demonstrates the Idle API",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "idle"
  ],
  "browser_action": {
    "default_icon": "sample-19.png"
  },
  "icons": {
    "16": "sample-16.png",
    "48": "sample-48.png",
    "128": "sample-128.png"
  },
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "{2431869e-11b8-4bef-ba80-7395eaaebc09}"
    }
  }
}