Yes sasl-md5 work with clear password, that is why to me the password of syncuser is defined in the base sasl2db.
In my ldap configuration, I have only the following line:
OlcAuthzRegexp: {0} " uid=syncuser, cn=DIGEST-MD5, cn=auth " " cn=syncuser, dc=xxx, dc=fr "
In my ldap base I thus have no entry "cn=syncuser,dc=xxx,dc=fr' defined.
In my ldapsearch command :
# ldapsearch -Y DIGEST-MD5-U syncuser -h localhost
Reads that rule OlcAuthzRegexp: {0} " for the user "uid=syncuser, cn=DIGEST-MD5, cn=auth " translates into ldap entry "cn=syncuser,cn=xxx,cn=fr".