/usr/ is in ruby-celluloid-pool 0.20.5-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/
/usr/lib/ruby/
/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/celluloid/
/usr/lib/ruby/vendor_ruby/celluloid/supervision/
/usr/lib/ruby/vendor_ruby/celluloid/supervision/container/
/usr/lib/ruby/vendor_ruby/celluloid/supervision/container/behavior/
/usr/lib/ruby/vendor_ruby/celluloid/supervision/container/behavior/pool.rb
/usr/lib/ruby/vendor_ruby/celluloid/supervision/container/pool.rb
/usr/lib/ruby/vendor_ruby/celluloid/pool.rb
/usr/share/
/usr/share/rubygems-integration/
/usr/share/rubygems-integration/all/
/usr/share/rubygems-integration/all/specifications/
/usr/share/rubygems-integration/all/specifications/celluloid-pool-0.20.5.gemspec
/usr/share/doc/
/usr/share/doc/ruby-celluloid-pool/
/usr/share/doc/ruby-celluloid-pool/copyright
/usr/share/doc/ruby-celluloid-pool/changelog.Debian.gz
/usr/share/doc/ruby-celluloid-pool/README.md