Earlier quoted context omitted.
Even web apps that you add to your home screen are subjected to this.
"Web applications added to the home screen are not part of Safari and thus have their own counter of days of use."[1] From WebKit: [1] https://webkit.org/blog/10218/full-third-party-cookie-blocki... A Note On Web Applications Added to the Home Screen As mentioned, the seven-day cap on script-writable storage is gated on after seven days of Safari use without user interaction on the site.” That is the case in Safari.…
This is a baffling word salad. So they are tracking days of use of home screen web apps... which sounds like it means that if you do not use the app for seven days the cache will be deleted... but they don't expect a web app to have its data deleted. What?