Modal Dialog Proposal

Hi WebAuthn,

As the chair of the Web Payments WG and co-author of this proposal I'd
appreciate your feedback.

The proposal came out of a need for cross-origin UI to facilitate payments
use cases where the payer and payee applications are in different origins.

We heard at TPAC that there are also use cases of interest to Web Authn
with similar requirements (such as SSO) so we'd appreciate your feedback.

The proposal was posted to WICG here and includes links to an explainer
with more details:
https://discourse.wicg.io/t/proposal-modal-window/3982

Thanks!

Adrian