Examine source code of Open in Colab Button

{
  "description": "Add-on that adds a button, «Open in Colab», to the header of IPython notebook in Gist and GitHub",
  "manifest_version": 2,
  "short_name": "Open notebook in Colab",
  "name": "Open in Colab",
  "version": "1.0",
  "icons": {
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "applications": {
    "gecko": {
      "id": "@nbincolab",
      "strict_min_version": "57.0"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "js/onic.js"
      ]
    }
  ],
  "permissions": [
    "activeTab"
  ]
}