Examine source code of Google Drive Percentage

{
  "manifest_version": 2,
  "name": "Google Drive Percentage",
  "version": "0.0.1",
  "description": "Displays zipping progress in percentage when downloading stuff from Google Drive",
  "icons": {
    "48": "assets/icon48.png",
    "128": "assets/icon128.png"
  },
  "content_scripts": [
    {
      "js": [
        "dist/index.js"
      ],
      "run_at": "document_start",
      "matches": [
        "*://drive.google.com/drive/*"
      ]
    }
  ]
}