Ok, if this is a concern for people, I’m now looking this up on MDN rather than taking the risk of Claude hallucinating things:
Safari
Starting with macOS 14 and iOS 17, Safari allots up to around 20% of the total disk space for each origin. If the user has saved it as a web app on the Home Screen or the Dock, this limit is increased to up to 60% of the disk size. For privacy reasons, cross-origin frames have a separate quota, amounting to roughly 1/10 of their parents.
So this would suggest significantly bigger limits than 50MB for iOS, especially when adding SB as a home screen app (like you should 
), this should be multiple GB in practice.
For Chrome browsers:
In browsers based on the Chromium open-source project, including Chrome and Edge, an origin can store up to 60% of the total disk size in both persistent and best-effort modes.
For example, if the device has a 1 TiB hard drive, the browser will allow an origin to use up to 600 GiB.
And Firefox:
In Firefox, the maximum storage space an origin can use in best-effort mode is whichever is the smaller of:
- 10% of the total disk size where the profile of the user is stored.
- Or 10 GiB, which is the group limit that Firefox applies to all origins that are part of the same eTLD+1 domain.
Origins for which persistent storage has been granted can store up to 50% of the total disk > size, capped at 8 TiB, and are not subject to the eTLD+1 group limit.
For example, if the device has a 500 GiB hard drive, Firefox will allow an origin to store up to:
In best-effort mode: 10 GiB of data, which is the eTLD+1 group limit.
In persistent mode: 250 GiB, which is 50% of the total disk size.
Not sure if Firefox has different behavior on Android, but this also seems plenty.