/etc/dpkg/shlibs.default is in dpkg-dev 1.16.1.2ubuntu7.7.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 | # dpkg shlibs defaults file
#
# This file contains shlibs entries that are used as a last resort when
# no matching entries are found elsewhere. For more information see the
# dpkg-shlibdeps(1) manual page.
#
# <library name> <version/soname> <dependencies>
|