The page has two summary messages https://www.wikidata.org/wiki/Special:SetLabelDescriptionAliases?uselang=qqx

• wikibase-setlabeldescriptionaliases-summary (no matches in code search)
• setlabeldescriptionaliases-summary (no matches in code search, automatically used by mw core if exists)

Latter has custom override on Wikidata
https://www.wikidata.org/w/index.php?title=MediaWiki:Setlabeldescriptionaliases-summary&action=history

Product decision:

• Should this be part of Wikibase defaults? If so it should be added to the json files
• Should this only be for Wikidata? If so, it should be added to WikimediaMessages
• Should it not be there or decided by the community? If so, leave or delete the local customization

Hello

However, all the other messages on the Special:SetLabelDescriptionAliases (qqx) page are in the code (mediawiki/extensions/Wikibase/+/refs/heads/master/repo/i18n/en.json, look for setlabeldescriptionaliases and the others). Why wouldn't the message I'm proposing be there?

I can try to provide some answers:

• It can be found by default (due to the complexity of other Wikibases).
• This section is not found in other projects, so it's reserved for Wikidata. It needs to be added to WikimediaMessages; otherwise, the community cannot translate this section, as requested.
• The majority of the community wouldn't understand and would make a biased decision. The existence of messages in other languages ​​locally means that it's missing from TranslateWiki.