Difference bw `rails new myapp --skip-sprockets` and `rails new myapp` for Rails 4.2.1

gistfile1.txt

diff -r tmp3/myapp/config/application.rb tmp2/myapp/config/application.rb
3,12c3
< require "rails"
< # Pick the frameworks you want:
< require "active_model/railtie"
< require "active_job/railtie"
< require "active_record/railtie"
< require "action_controller/railtie"
< require "action_mailer/railtie"
< require "action_view/railtie"
< # require "sprockets/railtie"
< require "rails/test_unit/railtie"
---
> require 'rails/all'
diff -r tmp3/myapp/config/environments/development.rb tmp2/myapp/config/environments/development.rb
24a25,37
>   # Debug mode disables concatenation and preprocessing of assets.
>   # This option may cause significant delays in view rendering with a large
>   # number of complex assets.
>   config.assets.debug = true
> 
>   # Asset digests allow you to set far-future HTTP expiration dates on all assets,
>   # yet still be able to expire them through the digest params.
>   config.assets.digest = true
> 
>   # Adds additional error checking when serving assets at runtime.
>   # Checks for improperly declared sprockets dependencies.
>   # Raises helpful error messages.
>   config.assets.raise_runtime_errors = true
diff -r tmp3/myapp/config/environments/production.rb tmp2/myapp/config/environments/production.rb
26a27,38
>   # Compress JavaScripts and CSS.
>   config.assets.js_compressor = :uglifier
>   # config.assets.css_compressor = :sass
> 
>   # Do not fallback to assets pipeline if a precompiled asset is missed.
>   config.assets.compile = false
> 
>   # Asset digests allow you to set far-future HTTP expiration dates on all assets,
>   # yet still be able to expire them through the digest params.
>   config.assets.digest = true
> 
>   # `config.assets.precompile` and `config.assets.version` have moved to config/initializers/assets.rb
Only in tmp2/myapp/config/initializers: assets.rb
diff -r tmp3/myapp/Gemfile tmp2/myapp/Gemfile
7a8,11
> # Use SCSS for stylesheets
> gem 'sass-rails', '~> 5.0'
> # Use Uglifier as compressor for JavaScript assets
> gem 'uglifier', '>= 1.3.0'