Notifications utilize native system integration where supported

Cramming multi-item data into a newline-joined type: 'basic' message discards rich OS notification affordances — per-item titles, action buttons, progress bars, image thumbnails — that users expect from native apps on macOS, Windows, and ChromeOS. Worse, requireInteraction: true on informational notifications blocks the OS from auto-dismissing them, forcing users to manually dismiss every stale update. The extension feels second-class, and on ChromeOS it violates platform UX conventions that reviewers flag during Chrome Web Store submission.

Use type: 'list' for multi-item notifications with one row per item, type: 'progress' for long-running operations, and buttons for actionable quick replies. Reserve requireInteraction: true only for time-critical alerts. In background.js:

chrome.notifications.create({
  type: 'list',
  iconUrl: 'icons/48.png',
  title: '3 New Messages',
  message: '',
  items: [{ title: 'Alice', message: 'hi' }, { title: 'Bob', message: 'ok' }],
  buttons: [{ title: 'View All' }],
});