As others mentioned, this is backed by the "open" standard FedCM. While this seems like an open play on the surface (and the standard is open), in practice this is a highly anti-competitive and will just lead to Google being in even more control of the web.

The vast majority of users will chose the default for identity. On Chrome this is Google. On Android this is Google. Even on iOS this may be Google because identity is often tied to email and Apple does not have a strong email story. Identity is huge. It gives you moat that outlives platforms.

And all the while, Google gets to claim this standard is open, while in practice this is clearly intended as a monopolistic move to increase their share of identity on the web.

If they were forced to show a randomized list of identity providers a user needs to choose from (similar to search engines on iOS), I bet you they would reconsider this whole approach. But by the time regulators figure out what's going on, they will have already cemented their lead.

This "standard" also seems interestingly timed with respect to Passkey adoption, too. If one were feeling pessimistic enough, it almost seems too easy to suggest some interests exist here that want to muddy the sign-in waters to capture users considering switching to Passkeys before they actually switch to Passkeys.