Examine source code of dedup

{
  "name": "dedup",
  "description": "Close duplicate tabs when a tab with the same url is opened",
  "manifest_version": 2,
  "applications": {
    "gecko": {
      "id": "dedup@uxploration.io",
      "strict_min_version": "52.0"
    }
  },
  "version": "0.0.3resigned1",
  "background": {
    "scripts": [
      "background/background.js"
    ]
  },
  "permissions": [
    "tabs"
  ]
}