manifest.json

{
  "name": "10tabs",
  "version": "1.0",
  "description": "limits the open tabs to 20 - I just like the name 10tabs ;) - when you try to open 21st tab it sends you to the least recently used tab",
  "permissions": [
    "tabs"
  ],
  "background": {
    "persistent": false,
    "scripts": ["manager.js"]
  },
  "manifest_version": 2
}