If you develop a pure frameworkless Ruby application or embed Ruby and don't need any of the listed integrations, you can depend on the airbrake-ruby gem and ignore this gem entirely.

Rack::Session was moved to a separate gem. Previously, Rack::Session was part of the rack gem. Not every application needs it, and it increases the security surface area of the rack, so it was decided to extract it into its own gem rack-session which can be updated independently.

Doing everything PID 1 needs to do and nothing else. Things like reading environment files, changing users, process supervision are out of scope for Tini (there are other, better tools for those)

'm open to considering adding this to core but it's such a rare need (given that you're the first to ever ask for it, and I've never wanted or needed an around(:all) hook) I have a preference for keeping it in external gem if we can do so w/o hooking into rspec's internals

With the new plugin based architectue, the library has really small core. Everything else is built around as a plugin.