When variants conversion mark -{}- is used on searchbuttonlabel and default field, it is supposed to show different variants. But now only raw wikitext is shown (like -{zh-cn:foo; zh-tw:bar;}-). It is believed that the conversion works yesterday but is down for now. Here and here are some examples.
@A2093064 has tested all Chinese sites and the result is it does not work on all the wikis except Beta Cluster.
It seem happened after the deploy of 1.31.0-wmf.7 .