Currently, the translation module of the MediaWiki set the universal Chinese translation function and offered the conversion system to the zh-HANT, zh-HANS, zh-HANT-tw, zh-HANS-cn, zh-HANS-sg, zh-HANT-mo, zh-HANS-my and zh-HANT-hk. However, when a user set the preferred language variant (e.g. zh-HANT-tw), the translation page of zh still remains unconverted version (zh page).
The default page is unconverted (不轉換, 不转换, as the zh page) and cannot redirect to the preferred local variant page a user sets on the preferences.
I must click the menu to select the local variant page manually.
Other multilingual sites have the same problems (e.g. Meta).
I think that I found the problem.
In Chinese Wikipedia, the zh-xx conversion redirect is controlled by the "content language variant" in the preference:
However, the function on the Commons, Meta and other multilingual sites are not available.
So, I want to request that the "content language variant" function should be deployed to the multilingual sites.