The MobileFrontend extension [0] collapses lists of languages into a single language button that reveals languages in a JavaScript overlay however this language overlay does not surface language variants. A solution to this problem is much needed and would all end users by speeding up the load time of many pages. See this bug report for more information:
https://bugzilla.wikimedia.org/show_bug.cgi?id=58988

Students are required to read Wikimedia's general instructions [1] first. Patches should be submitted to Gerrit [3] and reference the bug report in the  commit message [2]. ideally the solution should be added to the beta mode of the MobileFrontend extension to allow testing and quicker merging, repository maintainers can help with this during the code review process.

[0] https://www.mediawiki.org/wiki/Extension:MobileFrontend [1] https://www.mediawiki.org/wiki/Google_Code-in#Instructions_for_GCI_students [2] https://www.mediawiki.org/wiki/Gerrit/Getting_started [3] https://www.mediawiki.org/wiki/Gerrit/Commit_message_guidelines#Referencing_bugs