[Privacy] Fate of metadata / authentication history when clearing browsing data

[markafoltz]

When a user clears browsing data, the user agent may want to clear metadata and the authentication history for Open Screen receivers (or give the user an option to do so).

This issue tracks what recommendation, if any, the spec should make around this situation.

[markafoltz]

Two references I've found in the W3C space around what "private browsing mode" means include:

W3C TAG Observations on Private Browsing Modes

and

Standardizing Privacy-Oriented Standards Deviations, in Web Standards (in the PING GitHub)

My reading of these documents is that while there is no attempt underway to standardize PBM, specs can provide some informative guidance on how they can be implemented in a way to improve user privacy when users activate a higher-privacy mode.

For OSP, I think this means partitioning the protocol state (including certificates) between normal browsing and private browsing mode, so another agent can't correlate activity between the two modes and be certain it's from the same agent. (Of course as knowledge of local IP addresses is currently essential to the functioning of the protocol, there's a limit to what can be achieved.)

I will defer on formulating a PR around this, perhaps this is an item we can call out in horizontal reviews for privacy.