/usr/lib/ruby/ is in ruby-rack-oauth2 1.2.1-2.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/rack/
/usr/lib/ruby/vendor_ruby/rack/oauth2/
/usr/lib/ruby/vendor_ruby/rack/oauth2.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/VERSION
/usr/lib/ruby/vendor_ruby/rack/oauth2/access_token/
/usr/lib/ruby/vendor_ruby/rack/oauth2/access_token.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/access_token/authenticator.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/access_token/bearer.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/access_token/legacy.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/access_token/mac/
/usr/lib/ruby/vendor_ruby/rack/oauth2/access_token/mac.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/access_token/mac/sha256_hex_verifier.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/access_token/mac/signature.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/access_token/mac/verifier.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/client/
/usr/lib/ruby/vendor_ruby/rack/oauth2/client.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/client/error.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/client/grant/
/usr/lib/ruby/vendor_ruby/rack/oauth2/client/grant.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/client/grant/authorization_code.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/client/grant/client_credentials.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/client/grant/password.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/client/grant/refresh_token.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/debugger/
/usr/lib/ruby/vendor_ruby/rack/oauth2/debugger.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/debugger/request_filter.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/
/usr/lib/ruby/vendor_ruby/rack/oauth2/server.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/abstract/
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/abstract.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/abstract/error.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/abstract/handler.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/abstract/request.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/abstract/response.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/authorize/
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/authorize.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/authorize/code.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/authorize/error.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/authorize/extension/
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/authorize/extension.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/authorize/extension/code_and_token.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/authorize/token.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/resource/
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/resource.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/resource/bearer/
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/resource/bearer.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/resource/bearer/error.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/resource/error.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/resource/mac/
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/resource/mac.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/resource/mac/error.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/token/
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/token.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/token/authorization_code.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/token/client_credentials.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/token/error.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/token/extension/
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/token/extension.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/token/extension/jwt.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/token/password.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/server/token/refresh_token.rb
/usr/lib/ruby/vendor_ruby/rack/oauth2/util.rb