Examine source code of Unv.is

{
  "manifest_version": 2,
  "name": "Unv.is",
  "version": "1.2resigned1",
  "default_locale": "en",
  "description": "Adds a context menu item to open links through https://unv.is.",
  "icons": {
    "48": "icons/icon-48.png"
  },
  "permissions": [
    "contextMenus",
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{03e59fc6-4f6f-43b6-b02e-4c7626d6c7cd}"
    }
  }
}