/lib/systemd/system/krb5-kdc.service.d/slapd-before-kdc.conf is in krb5-kdc-ldap 1.12.1+dfsg-19+deb8u4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2
[Unit] After=slapd.service