Rack-based asset packaging system
Ruby on Rails stylesheet engine for Sass
Sprockets Rails integration
rubyonrails.org site anno 2015
Rails application preloader
Connects business objects and REST web services
Rails observer (removed from core in Rails 4.0)
A virtual machine for Ruby on Rails core development
A gem to automate using jQuery with Rails
Jbuilder: generate JSON objects with a Builder-style DSL
Ruby on Rails unobtrusive scripting adapter for jQuery
Extracting DomAssertions and SelectorAssertions from ActionView.
Protect attributes from mass-assignment in ActiveRecord models.
CoffeeScript adapter for the Rails asset pipeline. Also adds support for .coffee views.
Active Record's Session Store extracted from Rails