https://zh.wikivoyage.org/wiki/Special:ApiSandbox#action=query&format=json&meta=siteinfo&utf8=1&siprop=namespacealiases
Steps to reproduce:
# Open any page in project namespace on Chinese Wikiquote or Wikivoyage, for example [[ https://zh.wikiquote.org/wiki/Wikiquote:%E4%BA%92%E5%8A%A9%E5%AE%A2%E6%A0%88 | the Wikiquote one ]] and [[ https://zh.wikivoyage.org/w/index.php?title=Wikivoyage:%E6%B6%82%E9%B8%A6%E5%A2%99&oldid=156764 | the Wikivoyage one ]]
# Set the `Content language variant` to anything //other than// `zh` in Special:Preferences, for example `zh-Hans - 中文(简体)`
# Reload the page and look at the namespace part of the page title. It will randomly show `维基新闻`, `维基文库`, `维基语录`, `维基导游` or `维基教科书` (may not complete).
# Reload the page again and the namespace may change. If not, try purging the page or visiting another project page and look at the namespace part in page title.
Notes:
* `维基新闻`, `维基文库`, `维基语录`, `维基导游` or `维基教科书` are translated as `Wikinews`, `Wikisource`, `Wikiquote`, `Wikivoyage` and `Wikibooks`, respectively. In other words, these page titles are shown as if they are in another project.
* The correct namespace alias should be `维基语录` (or `維基語錄`) and `维基导游` (or `維基導遊`) for [[ https://zh.wikiquote.org/w/api.php?action=query&meta=siteinfo&utf8=1&siprop=namespacealiases | Wikiquote ]] and [[ https://zh.wikivoyage.org/w/api.php?action=query&meta=siteinfo&utf8=1&siprop=namespacealiases | Wikivoyage ]], as per the `meta=siteinfo` API result.
* Things work fine if the content language variant is set to `zh`.