[[ https://www.mediawiki.org/wiki/Repositories_with_Ruby_code | Repositories ]] that have ruby code have `Gemfile`. Example from mediawiki-selenium:
```
#ruby=ruby-2.1.1
#ruby-gemset=mediawiki_selenium
source "https://rubygems.org"
gemspec
```
The first two lines are for RVM. We do not officially recommend RVM any more. The lines should be removed.
```
$ grep -R -F 'gemset' .
./mediawiki/ruby/api/Gemfile:# ruby-gemset=mediawiki_api
./mediawiki/vagrant/mediawiki/extensions/ArticleFeedbackv5/Gemfile:# ruby-gemset=browsertests
./mediawiki/vagrant/mediawiki/extensions/Flow/Gemfile:#ruby-gemset=Flow
./mediawiki/vagrant/mediawiki/extensions/Gather/Gemfile:# ruby-gemset=Gather
./mediawiki/vagrant/mediawiki/extensions/MobileFrontend/Gemfile:# ruby-gemset=MobileFrontend
./mediawiki/vagrant/mediawiki/extensions/PageTriage/Gemfile:#ruby-gemset=browsertests
./mediawiki/vagrant/mediawiki/extensions/PdfHandler/Gemfile:#ruby-gemset=browsertests
./mediawiki/vagrant/mediawiki/extensions/PoolCounter/Gemfile:#ruby-gemset=PoolCounter
./mediawiki/vagrant/mediawiki/extensions/QuickSurveys/Gemfile:# ruby-gemset=QuickSurveys
./mediawiki/vagrant/mediawiki/extensions/UploadWizard/Gemfile:#ruby-gemset=UploadWizard
./mediawiki/vagrant/mediawiki/extensions/VisualEditor/Gemfile:# ruby-gemset=VisualEditor
./mediawiki/vagrant/mediawiki/extensions/ZeroPortal/Gemfile:#ruby-gemset=ZeroPortal
./mediawiki/vagrant/mediawiki/Gemfile:# ruby-gemset=core
```