Bugzilla

So my understanding is, a fingerprinter could get info about the disk space using two methods:
- Filling browser with junk until it hits quota error
- Calling navigator.storage.estimate()

The first option (IMO) wouldn't be very desirable for fingerprinters. For the following reasons,
- Most fingerprinters need to be fast, trying to hit the cap would take a while.
- User experience would suffer by the IO
- Junk data would have to be reliably cleared out before user exits page. For example, if the fingerprinter doesn't reach 10GBs of quota before the user exits the page, then that data is going to take a lot of space as long as it isn't not evicted, and this process would need to run per origin.

So, IMO it is enough to prevent the quick way to get disk space and keep the internal checks without any modifications/spoofing. The goal isn't to break websites requiring large storage, but to prevent fingerprinters from gathering disk space in a quick way. [D223842](https://phabricator.services.mozilla.com/D223842) should also set the group limit to 1gb (after I fix the typo).

So my understanding is, a fingerprinter could get info about the disk space using two methods:
- Filling browser with junk until it hits quota error
- Calling navigator.storage.estimate()

The first option (IMO) wouldn't be very desirable for fingerprinters. For the following reasons,
- Most fingerprinters need to be fast, trying to hit the cap would take a while.
- User experience would suffer by the IO
- Junk data would have to be reliably cleared out before user exits page. For example, if the fingerprinter doesn't reach 10GB of quota before the user exits the page, then that data is going to take a lot of space as long as it isn't not evicted, and this process would need to run per origin.

So, IMO it is enough to prevent the quick way to get disk space and keep the internal checks without any modifications/spoofing. The goal isn't to break websites requiring large storage, but to prevent fingerprinters from gathering disk space in a quick way. [D223842](https://phabricator.services.mozilla.com/D223842) should also set the group limit to 1gb (after I fix the typo).