[css-ruby-1] "zh-Hanb" or "zh-Hant", which is correct for 30% font-size rule?

[MurakamiShinyu]

https://drafts.csswg.org/css-ruby/#default-ua-ruby

rtc:lang(zh-TW), :not(rtc) > rt:lang(zh-TW),
rtc:lang(zh-Hanb), :not(rtc) > rt:lang(zh-Hanb), {
  font-size: 30%; }               /* bopomofo */

I think the "zh-Hanb" means Chenese with bopomofo script, but I found the following descriptin in the "Changes since the 2 December 2021 WD":

• Added zh-Hant to rule applying font-size: 30% to ruby annotations in HTML.

"zh-Hanb" or "zh-Hant", which is correct?

[Loirooriol]

Context: #775 3800bae