Code
Avoids application cache
The application cache technology has been removed from most browser and is no longer part of any standard.
How the audit works
This audit fails when Lighthouse finds a reference to the Application Cache manifest in a page's
<html> tag. For example, this markup causes the audit to fail:
<html manifest="example.appcache"> ...</html>
Fixing the problem
To pass this audit, remove the manifest from your page, and use the Cache API via a service worker instead.
To migrate from the Application Cache to service workers, consider using the sw-appcache-behavior library. This library generates a service-worker-based implementation of the behavior defined in an Application Cache manifest.