On pages like https://www.wikifunctions.org/?uselang=zh, the "Project chat" and "Current status" links are shown in English.
These links should use messages which can be translated on Translatewiki, so that users can easily add translations for them.
I don't think this is a concept that the Translate extension supports, sadly. (Unless you know of it working somewhere like this?)
They are translated in pages like https://www.wikifunctions.org/wiki/MediaWiki:Villagepump/zh (cf https://www.wikidata.org/wiki/MediaWiki:Villagepump/zh) and https://www.wikifunctions.org/wiki/MediaWiki:Status.
The way this is normally done is by adding the messages to a repository.
See for example project-specific repositories like
or the generic repository for Wikimedia-specific messages:
But this message will be only used in Wikifunctions, since in other wikis Village Pump will locate elsewhere.
If you don't want to put project-specific messages in the generic repository, then put them in a project-specific repository like Wikidata and the Incubator do?
An example of how big a difference it can make:
https://www.wikidata.org/wiki/MediaWiki:Queryservice was created in June 2017 and was moved to the Wikidata.org extension in July 2022, 5 years and 1 month later. There were only 12 existing translations to import (see commit). A year and a half later, there are now 43 translations (code search), over three times as many.