Hey folks :)
We'll be rolling out a new beta feature on August 26th/28th to Wikipedia, Wikisource and Wikiquote. It will add a new section to the sidebar of an article. This section will contain links to related articles in other sister projects. Which projects are shown can be configured per-wiki. You can find out more about it at https://www.mediawiki.org/wiki/Beta_Features/Other_projects_sidebar
If you have any questions about this please use the discussion page of https://www.mediawiki.org/wiki/Beta_Features/Other_projects_sidebar
Cheers Lydia