/usr/lib/x86_64-linux-gnu/mesa-egl/ld.so.conf is in libegl1-mesa-lts-xenial 11.2.0-1ubuntu2~trusty2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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/usr/lib/x86_64-linux-gnu/mesa-egl