/usr/lib/bfd-plugins/liblto_plugin.so is in gcc 4:7.3.0-3ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/bfd-plugins/../gcc/x86_64-linux-gnu/7/liblto_plugin.so
/usr/lib/bfd-plugins/../gcc/x86_64-linux-gnu/7/liblto_plugin.so