TLDR for anyone who doesn't want to read the whole post:
Passkeys are a thing you've probably seen replacing passwords for logins. They are, generally speaking, more secure and convenient to store.
Currently, there's no standard format, so it's hard to, say, transfer between Bitwarden and 1Password, or between your browser keychain and Bitwarden.
They're working on a standardized format to store and transfer passkeys, to avoid vendor lock-in.
The new standard would also improve the security of transferring logins. Current mechanisms use an unencrypted csv file. This would likely involve an encrypted, direct transfer.