Examine source code of Fire Auto Reloader

{
  "manifest_version": 2,
  "name": "Fire Auto Reloader",
  "short_name": "Tab Reloader",
  "description": "It reloads the current tab at a chosen interval",
  "version": "1.0",
  "icons": {
    "16": "assets/icon16.png",
    "48": "assets/icon48.png",
    "128": "assets/icon128.png"
  },
  "browser_action": {
    "default_icon": {
      "19": "assets/icon19.png",
      "38": "assets/icon38.png"
    },
    "default_popup": "popup.html",
    "default_title": "Reload this page every…"
  },
  "applications": {
    "gecko": {
      "id": "@tabreloader",
      "strict_min_version": "57.0"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "storage"
  ]
}