Thanks for taking the time to report this!

What are steps to see the problem?
What can be seen where and what is expected instead?

(In reply to Andre Klapper from comment #1)

Thanks for taking the time to report this!

What are steps to see the problem?
What can be seen where and what is expected instead?

Well, when you are at "zh.wikivoyage.org/wiki/首页", look at the tab on your browser, it display as "维基导游 (zh-hans)". However when you change your language in to zh-hant, zh-tw or zh-hk, it won't change in to "維基導遊 (zh-hant)". And also, like the en wikipedia, its web name display on the brower tab is "Wikipedia, the free encyclopedia", but zh.voy just has "维基导游 (Wikivoyage)", so the sitesubtitle "自由的旅遊指南 (free worldwide travel guide)" can not display out.

If you refer to the page <title> and the Wikivoyage logo, I can confirm that it does not change when switching to another Chinese variant.

Text in <title> is affected by message "pagetitle-view-mainpage" for main page and "pagetitle" for other pages; you can do customization there. To have different text of "pagetitle-view-mainpage" in different languages, it needs to be added to $wgForceUIMsgAsContentMsg. See bug 32547.

Regarding the logo, search for "#p-logo" in [[zh:MediaWiki:Common.css]].

Liangent: Thanks for sharing your knowledge here!

So, to sum up this bug:

1. The logo issue can be easily fixed by adding appropriate CSS rules to the MediaWiki:Common.css page (just copy them from zh.wikipedia and change the logo to suit your needs; I can create one if need be);
2. The main page title issue can be fixed by submitting a patch to add pagetitle-view-mainpage to $wgForceUIMsgAsContentMsg as suggested by Liangent in comment 4 — and I'm inclined to do that unless there is a good reason no to.

However, I am unable to reproduce the other problem mentioned in comment 2 related to the tagline: https://zh.wikivoyage.org/wiki/MediaWiki:Tagline currently holds the default value from Translatewiki.net. What should I do to make it display "From Wikipedia, the free encyclopedia"?

Thank you for everyone's comment, I have fixed this problem!

Not fixed - https://zh.wikivoyage.org/w/index.php?title=Wikivoyage:%E4%BA%92%E5%8A%A9%E5%AE%A2%E6%A0%88&oldid=prev&diff=38636#.E7.BB.B4.E5.9F.BA.E5.AF.BC.E6.B8.B8.E9.A6.96.E9.A1.B5.E6.A0.87.E9.A2.98.E7.B9.81.E7.AE.80.E8.BD.AC.E6.8D.A2.E5.8F.88.E6.8C.82.E4.BA.86

$wgForceUIMsgAsContentMsg hasn't been tweaked?

Change 148032 had a related patch set uploaded by Odder:
Set $wgForceUIMsgAsContentMsg for zhwikivoyage

https://gerrit.wikimedia.org/r/148032

Change 148032 merged by jenkins-bot:
Set $wgForceUIMsgAsContentMsg for zhwikivoyage

https://gerrit.wikimedia.org/r/148032

This should now be done. Thanks, Odder!