When installing, then removing (not purging) isc-dhcp-server, it leave
a broken apparmor config, leading to the following error:

Jun 05 12:19:02 rpadovani apparmor.systemd[155394]: AppArmor parser
error for /etc/apparmor.d in profile /etc/apparmor.d/usr.sbin.dhcpd at
line 72: Could not open 'dhcpd.d'
Jun 05 12:19:02 rpadovani apparmor.systemd[155458]: AppArmor parser
error for /etc/apparmor.d/usr.sbin.dhcpd in profile
/etc/apparmor.d/usr.sbin.dhcpd at line 72: Could not open 'dhcpd.d
Jun 05 12:19:02 rpadovani apparmor.systemd[155377]: Error: At least
one profile failed to load

It looks like the instruction at
https://salsa.debian.org/debian/isc-dhcp/-/blob/master/debian/apparmor/usr.sbin.dhcpd#L72
should be

#include if exists <dhcpd.d>

to allow the directory to remain empty. (see "#include mechanism" in
the apparmor.d(5) manpage)

Dear submitter,

as the package isc-dhcp has just been removed from the Debian archive
unstable we hereby close the associated bug reports.  We are sorry
that we couldn't deal with your issue properly.

For details on the removal, please see https://bugs.debian.org/1143544

The version of this package that was in Debian prior to this removal
can still be found using https://snapshot.debian.org/.

Please note that the changes have been done on the master archive and
will not propagate to any mirrors until the next dinstall run at the
earliest.

This message was generated automatically; if you believe that there is
a problem with it please contact the archive administrators by mailing
ftpmaster@ftp-master.debian.org.

Debian distribution maintenance software
pp.
Thorsten Alteholz (the ftpmaster behind the curtain)