/etc/apache2/conf-available/simplesamlphp.conf is in simplesamlphp 1.13.1-2+deb8u1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /etc/apache2/conf-available/../../simplesamlphp/apache.conf
/etc/apache2/conf-available/../../simplesamlphp/apache.conf