I compared "bundle list" between Rails 5.1.6 and 5.2.0 to identify the new or updated Ruby packages for Rails 5.2.0. Maybe this is useful information. I used my tool for that. [1]
## New packages in Rails 5.2.0
To install rubygem-rails - rubygem-activestorage 5.2.0 - rubygem-marcel - rubygem-mimemagic
To run rails application - rubygem-archive-zip - rubygem-bootsnap - rubygem-chromedriver-helper - rubygem-io-like - rubygem-msgpack
## Updated packages
To install rubygem-rails - rubygem-arel 8.0.0 to 9.0.0 - rubygem-websocket-driver 0.6.5 to 0.7.0
To run rails application - rubygem-capybara 2.14.3 to 3.0.2
[1] https://github.com/junaruga/rails-install-tester $ git clone https://github.com/junaruga/rails-install-tester.git $ diff rails/5.1.6/bundle_list.txt rails/5.2.0/bundle_list.txt $ diff rails/5.1.6/app/bundle_list.txt rails/5.2.0/app/bundle_list.txt
Regards, Jun