/usr/lib/x86_64-linux-gnu/ is in ruby-mmap2 2.2.7-1build2.
This file is owned by root:root, with mode 0o755.
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/usr/lib/x86_64-linux-gnu/rubygems-integration/
/usr/lib/x86_64-linux-gnu/rubygems-integration/2.5.0/
/usr/lib/x86_64-linux-gnu/rubygems-integration/2.5.0/extensions/
/usr/lib/x86_64-linux-gnu/rubygems-integration/2.5.0/extensions/x86_64-linux/
/usr/lib/x86_64-linux-gnu/rubygems-integration/2.5.0/extensions/x86_64-linux/2.5.0/
/usr/lib/x86_64-linux-gnu/rubygems-integration/2.5.0/extensions/x86_64-linux/2.5.0/mmap2-2.2.7/
/usr/lib/x86_64-linux-gnu/rubygems-integration/2.5.0/extensions/x86_64-linux/2.5.0/mmap2-2.2.7/gem.build_complete
/usr/lib/x86_64-linux-gnu/rubygems-integration/2.5.0/extensions/x86_64-linux/2.5.0/mmap2-2.2.7/mkmf.log
/usr/lib/x86_64-linux-gnu/rubygems-integration/2.5.0/extensions/x86_64-linux/2.5.0/mmap2-2.2.7/mmap//
/usr/lib/x86_64-linux-gnu/rubygems-integration/2.5.0/extensions/x86_64-linux/2.5.0/mmap2-2.2.7/mmap/mmap.so
/usr/lib/x86_64-linux-gnu/rubygems-integration/2.5.0/gems/
/usr/lib/x86_64-linux-gnu/rubygems-integration/2.5.0/gems/mmap2-2.2.7/
/usr/lib/x86_64-linux-gnu/rubygems-integration/2.5.0/gems/mmap2-2.2.7/ext/
/usr/lib/x86_64-linux-gnu/rubygems-integration/2.5.0/gems/mmap2-2.2.7/lib/
/usr/lib/x86_64-linux-gnu/rubygems-integration/2.5.0/gems/mmap2-2.2.7/lib/mmap/
/usr/lib/x86_64-linux-gnu/rubygems-integration/2.5.0/gems/mmap2-2.2.7/lib/mmap/version.rb
/usr/lib/x86_64-linux-gnu/rubygems-integration/2.5.0/gems/mmap2-2.2.7/lib/mmap.rb
/usr/lib/x86_64-linux-gnu/rubygems-integration/2.5.0/specifications/
/usr/lib/x86_64-linux-gnu/rubygems-integration/2.5.0/specifications/mmap2-2.2.7.gemspec