Examine source code of Environments keeper

{
  "name": "Environments keeper",
  "version": "3.0",
  "description": "Helps people working on multiple environments to switch to differen environments",
  "permissions": [
    "activeTab",
    "storage"
  ],
  "background": {
    "scripts": [
      "dist/background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "16-icon.png",
      "32": "32-icon.png",
      "48": "48-icon.png",
      "128": "128-icon.png"
    }
  },
  "icons": {
    "16": "16-icon.png",
    "32": "32-icon.png",
    "48": "48-icon.png",
    "128": "128-icon.png"
  },
  "manifest_version": 2
}