Shared lists not available in Safari PWA

[noyainrain]

After opening a link to a shared list, it is not available on the start page of the Safari PWA.

How to reproduce:

1. Open Listling in Safari mobile
2. Share > Add to Home Screen...
3. Open Listling in another browser
4. Create new list > Simple list
5. Share... for example via Messenger
6. Open shared link (will open in Safari mobile)
7. Open Listling PWA
8. Observe that the shared list is not available on the start page

A (poor) workaround for now would be to bookmark Listling (Share > Bookmark...) instead of installing the PWA (Share > Add to Home Screen...).

[noyainrain]

The possible cause may be that PWAs are isolated from Safari mobile, i.e. they don't share any storage, and shared links are not opened with the PWA, but Safari mobile (universal links are not supported).

It seems like service workers are cloned when installing a PWA with Safari, thus it would be possible to store authentication info in the Cache and make use of it on the first start of the PWA. However, there is no documentation on Safari PWAs and how the isolation is supposed to work, so I am rather hesitant to go down this road.

As a side note, in addition to the problems above, some apps open URLs in a SFSafariViewController, which is also isolated. For example see Telegram iOS.