@Operation(summary = "Fetch registered devices for username", parameters = @Parameter(name = "username", required = true, description = "The username to look up"))
    @GetMapping(path = "{username}", produces = MediaType.APPLICATION_JSON_VALUE)
    public Collection<? extends CredentialRegistration> fetch(
        @PathVariable final String username) {
        return registrationStorage.getObject().getRegistrationsByUsername(username);
    }
Fetch collection.

@param username the username
@return the collection
support/cas-server-support-webauthn-core/src/main/java/org/apereo/cas/webauthn/web/WebAuthnRegisteredDevicesEndpoint.java