Package: yubikey-ksm Version: 1.15-6 The shipped /etc/apache2/conf-enabled/yubikey-ksm.conf seems to have a syntax error, a <IfDefine> tag is open but a </IfModule> is closed. See: https://sources.debian.net/src/yubikey-ksm/1.15-6/debian/conf/apache.conf/