What do we talk about when we talk about First Party Sets? #134

The First Party Sets proposal continues to evolve and at the point has become pretty different from the initial proposal, especially with the idea of some sort of independent entity checking and potentially invalidating self-attested sets.

I'm curious where the participants in this group land in terms of approval of the current state of the proposal as well as if those that have supported it in the past continue to support its current state.

To be clearly upfront with my purposes here: I'm not sure First Party Sets continues to make sense. Chrome team clearly intends it to be a way to have lower security walls for cross-site communication, but all the other browsers have made clear they do not intend to use it that way. Some of their use cases seem to be centered around easier to accomplish URL decoration or login, but I am admittedly vague on this.

As a result, I'm wondering if participants in this group would continue to see a use in FPS that does not reliably drop cross-site security to some degree?

It might be helpful if @martinthomson or @johnwilander were able to speak in more detail to what the other uses they see in FPS are, either here in text, by linking to existing statements, or by sending a rep to talk to this idea in the upcoming meeting.