PSA: FedCM syntax changes for use other account and account labels

[Christian Biesinger]

Hello,

Based on feedback from other browser vendors (use other account, account labels), we are renaming some JSON values used by two of the recently launched FedCM features. We have worked with the partners who use these features and they have already updated their code, so there should be no compat impact.

New syntax for an identity provider to request a “use other account” button in the config file:

{

  "accounts_endpoint": "...",

  ...

  "supports_use_other_account": true,

  "modes": {

    "active": {

      "supports_use_other_account": true

    }

  }

}

The boolean is no longer nested inside a modes dict. It will only be used for active mode, because passive mode is intended to be a less intrusive sign-in method, so we want to keep the dialog smaller. This matches the desired UI of our only interested partners so far.

New syntax for account labels:

In the accounts endpoint:

{

  "id": "...",

  ...

  "label_hints": ["label1"],

  "labels": ["label1"]

}

In the config file:

{

  "accounts_endpoint": "...",

  ...

  "account_label": "label1",

  "accounts": {

    "include": "label1"

  }

}

This change will ship in Chrome 137.

Thanks,

Christian on behalf of the Web Identity team