Examine source code of KITVideofy

{
  "manifest_version": 2,
  "name": "KITVideofy",
  "version": "1.3",
  "description": "When playing a stream video on ilias.studium.kit.edu this addon opens a new window with the downloadable video. To download it automatically, install KITDownloadify.",
  "icons": {
    "48": "icons/border-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://ilias.studium.kit.edu/*streamVideo*"
      ],
      "js": [
        "videofy.js"
      ]
    }
  ]
}