/usr/lib/cyrus/cyrus-hardwired-config.txt is in cyrus-common 2.4.17+nocaldav-0+deb8u2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2
PACKAGE_VERSION 2.4.17+nocaldav-0+deb8u2 USE_DIR_FULL 0