/usr/src/gcc-8/debian/libx32gphobos68.lintian-overrides is in gcc-8-source 8-20180414-1ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 | # no multilib zlib for x32
libx32gphobos68 binary: embedded-library
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