It’s both.

Emergency access uses public key exchange and encryption/decryption to allow users to give a trusted emergency contact permission to access vault data in a zero knowledge encryption environment:

See documentation here: https://bitwarden.com/help/emergency-access/#%3A~%3Atext=Emergency+access+uses+public+key%2Cemergency+contact+(the+grantee).

For password management I moved to bitwarden as proton pass was not there yet. I like bitwardens’s zero knowledge emergency access. I can have emergency contacts access my account in the event I am no longer able to.