Examine source code of sverben.nl

{
  "name": "sverben.nl",
  "version": "1.5.0",
  "manifest_version": 2,
  "description": "Verkort links met sverben.nl",
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "19": "image.png",
      "38": "image.png"
    }
  },
  "permissions": [
    "contextMenus",
    "tabs"
  ]
}