Google Code-in

Register on translatewiki.net, clone the relevant Wikidata/Wikibase/MassAction repositories and address the following requests with appropriate changes to en.json and qqq.json files:

• https://translatewiki.net/wiki/Thread:Support/About_MediaWiki:Apihelp-wbremovereferences-example-1/sv
• https://translatewiki.net/wiki/Thread:Support/About_MediaWiki:Apihelp-wbsetsitelink-example-3/sv
• https://translatewiki.net/wiki/Thread:Support/About_MediaWiki:Apihelp-wbgetentities-param-languagefallback/ksh
• https://translatewiki.net/wiki/Thread:Support/About_MediaWiki:Apihelp-wbsearchentities-param-strictlanguage/uk
• https://translatewiki.net/wiki/Thread:Support/About_MediaWiki:Logentry-massaction-jobfailed/en
• https://translatewiki.net/wiki/Thread:Translating_talk:MediaWiki/About_MediaWiki:Logentry-massaction-jobfailed/en

The threads mention the message key which you have to look for in the code to understand how it's used. https://www.mediawiki.org/wiki/Manual:Messages_API and https://www.mediawiki.org/wiki/i18n explain how to work with system messages.