WNDT63 Updates

[kaycebasques]

• LH 2.5: Serve images as WebP, Does not images with appropriate aspect ratios, Avoids frontend JS libraries with known security vulnerabilities, no browser errors logged to the console
• Link to LH audit references
• Mention that chrome.debugger API is now available to extensions thanks to the multi-client work
• Explain background sync better
• Check PR reviews for more updates
• Add a tip. Use inline feedback to gauge community sentiment

[kaycebasques]

Background Sync

Overview

1. Web page sends a background sync notification. That notification is sent through the "background sync manager"
2. If the browser is online, background sync manager delivers the notification.
3. If the browser is offline, background sync manager holds the notification. Notification is persisted even across browser restart.
4. Once the browser goes back online, notification is delivered to SW.
5. If SW event handle fails (e.g. throws), event is restarted at some point.

UX Notes

• This feature isn't intended to be used in offline mode. See overview above. The BG Sync Mgr would never send the notification while offline, so this is nonsensical state. DevTools could admittedly improve UX around this scenario.
• Should note the regression where SW net requests succeed in offline mode? Even though it's now a non-issue?