About [[MediaWiki:Apihelp-translationaids-param-group/ksh]]

OPEN This issue is open, waiting for action by Nike

Needs Documentation.

• A primary group or the primary group?
• What is a/the primary group?

https://www.mediawiki.org/wiki/Help:Extension:Translate/Glossary

Thanks, but the this still doesn't explicitly say which primary group is used. The primary group of the specified message? A(nother) primary group?

More in general, what does "Message group the message belongs to" mean?[1] Are there multiple options and what are the effects? If any message group of the message is fine, saying "A message group" would help, but we'd still have to explain how to choose among the multiple options.

Each message can belong to one and only one primary group. The specified group can affect some translations aids like message checks.