/usr/ is in ruby-cairo-gobject 3.2.4-1.
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/cairo-gobject.rb
/usr/lib/x86_64-linux-gnu/
/usr/lib/x86_64-linux-gnu/ruby/
/usr/lib/x86_64-linux-gnu/ruby/vendor_ruby/
/usr/lib/x86_64-linux-gnu/ruby/vendor_ruby/2.5.0/
/usr/lib/x86_64-linux-gnu/ruby/vendor_ruby/2.5.0/cairo_gobject.so
/usr/share/
/usr/share/doc/
/usr/share/doc/ruby-cairo-gobject/
/usr/share/doc/ruby-cairo-gobject/copyright
/usr/share/rubygems-integration/
/usr/share/rubygems-integration/2.5.0/
/usr/share/rubygems-integration/2.5.0/specifications/
/usr/share/rubygems-integration/2.5.0/specifications/cairo-gobject-3.2.4.gemspec
/usr/share/doc/ruby-cairo-gobject/changelog.Debian.gz