Stopwatch for Google Sheets

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 3,
  "name": "Stopwatch for Google Sheets",
  "description": "Adds a stopwatch to Google Sheets.",
  "version": "1.4",
  "icons": {
    "48": "timer48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://docs.google.com/spreadsheets/d/*/edit*"
      ],
      "js": [
        "timer.js"
      ]
    }
  ]
}