Nightly
Yab 0.46.32
Bitwarden's passkeys work on Chromium tabs: its passkey window opens, and choosing a passkey signs you in without closing the site's tab.
Fixed
Passkeys
Bitwarden and other password managers can offer their passkeys on Chromium tabs: their passkey window opens, and choosing a passkey signs you in.
Extensions
A window an extension opens on a Chromium tab, such as Bitwarden's passkey window, is a plain window with just its page, as in Chrome, instead of a Small Window.
Extensions
Closing a window an extension opened, such as Bitwarden's passkey window, no longer closes the site's tab.
Passkeys
Passkeys work in a site's embedded frames that are allowed to use them, and Chromium tabs check every passkey request the way Chrome does before Yab's passkey sheet answers it.