FedCM bundle: Continuation API, account labels, custom parameters, scopes

[cbiesinger]

WebKittens

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Title of the spec

FedCM bundle: Continuation API, account labels, custom parameters, scopes

URL to the spec

n/a

URL to the spec's repository

https://github.com/fedidcg/FedCM/

Issue Tracker URL

No response

Explainer URL

see below

TAG Design Review URL

w3ctag/design-reviews#945

Mozilla standards-positions issue URL

n/a

WebKit Bugzilla URL

No response

Radar URL

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Description

This bundles a few features that we would like to launch at the same time:

Continuation API:
https://github.com/fedidcg/FedCM/issues/555

This lets the IDP open a popup window to finish the sign-in flow after potentially collecting additional information.

Parameters API:
https://github.com/fedidcg/FedCM/issues/556

This lets RPs pass additional data to the ID assertion endpoint

Scope API:
https://github.com/fedidcg/FedCM/issues/559

This lets RPs bypass the data sharing prompt in favor of the IDP prompting

Scaling well-known:
w3c-fedid/FedCM#552

This lets IDPs use different config files in different contexts without weakening FedCM privacy properties, by allowing one accounts endpoint for the eTLD+1 (instead of one config file, which is more limiting than necessary)

Account labels:
w3c-fedid/FedCM#553

Combined with the previous proposal, this allows filtering the account list per config file without providing additional entropy to the IDP.