/usr/lib/ruby/ is in ruby-rbnacl 5.0.0-3.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/rbnacl/
/usr/lib/ruby/vendor_ruby/rbnacl/aead/
/usr/lib/ruby/vendor_ruby/rbnacl/aead/base.rb
/usr/lib/ruby/vendor_ruby/rbnacl/aead/chacha20poly1305_ietf.rb
/usr/lib/ruby/vendor_ruby/rbnacl/aead/chacha20poly1305_legacy.rb
/usr/lib/ruby/vendor_ruby/rbnacl/auth.rb
/usr/lib/ruby/vendor_ruby/rbnacl/boxes/
/usr/lib/ruby/vendor_ruby/rbnacl/boxes/curve25519xsalsa20poly1305/
/usr/lib/ruby/vendor_ruby/rbnacl/boxes/curve25519xsalsa20poly1305/private_key.rb
/usr/lib/ruby/vendor_ruby/rbnacl/boxes/curve25519xsalsa20poly1305/public_key.rb
/usr/lib/ruby/vendor_ruby/rbnacl/boxes/curve25519xsalsa20poly1305.rb
/usr/lib/ruby/vendor_ruby/rbnacl/group_elements/
/usr/lib/ruby/vendor_ruby/rbnacl/group_elements/curve25519.rb
/usr/lib/ruby/vendor_ruby/rbnacl/hash/
/usr/lib/ruby/vendor_ruby/rbnacl/hash/blake2b.rb
/usr/lib/ruby/vendor_ruby/rbnacl/hash/sha256.rb
/usr/lib/ruby/vendor_ruby/rbnacl/hash/sha512.rb
/usr/lib/ruby/vendor_ruby/rbnacl/hash.rb
/usr/lib/ruby/vendor_ruby/rbnacl/hmac/
/usr/lib/ruby/vendor_ruby/rbnacl/hmac/sha256.rb
/usr/lib/ruby/vendor_ruby/rbnacl/hmac/sha512.rb
/usr/lib/ruby/vendor_ruby/rbnacl/hmac/sha512256.rb
/usr/lib/ruby/vendor_ruby/rbnacl/init.rb
/usr/lib/ruby/vendor_ruby/rbnacl/key_comparator.rb
/usr/lib/ruby/vendor_ruby/rbnacl/libsodium/
/usr/lib/ruby/vendor_ruby/rbnacl/libsodium/version.rb
/usr/lib/ruby/vendor_ruby/rbnacl/libsodium.rb
/usr/lib/ruby/vendor_ruby/rbnacl/one_time_auths/
/usr/lib/ruby/vendor_ruby/rbnacl/one_time_auths/poly1305.rb
/usr/lib/ruby/vendor_ruby/rbnacl/password_hash/
/usr/lib/ruby/vendor_ruby/rbnacl/password_hash/argon2.rb
/usr/lib/ruby/vendor_ruby/rbnacl/password_hash/scrypt.rb
/usr/lib/ruby/vendor_ruby/rbnacl/password_hash.rb
/usr/lib/ruby/vendor_ruby/rbnacl/random.rb
/usr/lib/ruby/vendor_ruby/rbnacl/secret_boxes/
/usr/lib/ruby/vendor_ruby/rbnacl/secret_boxes/xsalsa20poly1305.rb
/usr/lib/ruby/vendor_ruby/rbnacl/self_test.rb
/usr/lib/ruby/vendor_ruby/rbnacl/serializable.rb
/usr/lib/ruby/vendor_ruby/rbnacl/signatures/
/usr/lib/ruby/vendor_ruby/rbnacl/signatures/ed25519/
/usr/lib/ruby/vendor_ruby/rbnacl/signatures/ed25519/signing_key.rb
/usr/lib/ruby/vendor_ruby/rbnacl/signatures/ed25519/verify_key.rb
/usr/lib/ruby/vendor_ruby/rbnacl/signatures/ed25519.rb
/usr/lib/ruby/vendor_ruby/rbnacl/simple_box.rb
/usr/lib/ruby/vendor_ruby/rbnacl/sodium/
/usr/lib/ruby/vendor_ruby/rbnacl/sodium/version.rb
/usr/lib/ruby/vendor_ruby/rbnacl/sodium.rb
/usr/lib/ruby/vendor_ruby/rbnacl/test_vectors.rb
/usr/lib/ruby/vendor_ruby/rbnacl/util.rb
/usr/lib/ruby/vendor_ruby/rbnacl/version.rb
/usr/lib/ruby/vendor_ruby/rbnacl.rb