https://fidoalliance.org/specs/fido-u2f-v1.2-ps-20170411/fid...
has a clear description in the "Allowing for Inexpensive U2F Devices" section.
For webauthn, they don't use key handle terminology anymore, but the same fuctionality is provided by the "Credential ID":
https://www.w3.org/TR/webauthn-2/#credential-id
https://fidoalliance.org/specs/fido-u2f-v1.2-ps-20170411/fid...
has a clear description in the "Allowing for Inexpensive U2F Devices" section.
For webauthn, they don't use key handle terminology anymore, but the same fuctionality is provided by the "Credential ID":
https://www.w3.org/TR/webauthn-2/#credential-id