SameParty could convey contextual information to user

[cfredric]

Paraphrased from minutes of PrivacyCG meeting on Dec 10 2020, summarizing @johnwilander's comment:

It would be nice if the SameParty attribute could convey contextual information from the site developer to the user, e.g. what functionality the cross-site cookie usage would enable. This information could be displayed to the user in a permission prompt (along with how long the cookie would last), which the user would have the option of accepting or not. If accepted, the user agent would store the cookie and send it according to SameParty semantics.

(@johnwilander, please clarify/correct this if I've misinterpreted your comment! Thanks.)

[martinthomson]

The correct link is https://github.com/privacycg/meetings/blob/main/2020/telcons/12-10-minutes.md

I think that the quote is:

Also concerned about FPS in general. We also want ways to understand why cookies are being shared. This attribute for cookies would not lead to any automatic access, e.g. it could be a way to signal that a third-party domain is "the login domain for" the first-party web site, and then browser could appropriately modify the text in a prompt, the duration that access lasts for, etc. Then could associate the changed permissions with a specific cookie, rather than all cookies for a domain.

I will note that this issue has been cited as Apple support for SameParty cookies. I wasn't at the meeting, and I not not John, but I had a hard time interpreting this as supportive. Did you ask for an official position from WebKit?