CLDRFile.getConstructedBaileyValue()'s source has a "TODO: make more useful" comment. And indeed, a null xpath is returned for something such as the name of zh-Hans "Chinese (Simplified)".
In the SurveyTool UI, this produces a useless "Jump to Original" link (such as in the sidebar on https://st.unicode.org/cldr-apps/v#/yo/Languages_E_J/7bbb0dfa5b2ebec9 ) that goes back to the same item.
The UI should detect this case: if fallbackXpid is not set and fallbackLocale is the same as the current locale, the message should change to say something else, perhaps such as “Constructed Value: please see other items”.
Ideally, CLDRFile.getConstructedBaileyValue would return a list of the source xpids (in the current locale is fine) which are used, such as “Chinese”(language) and “Simplified”(script). Then Jump to Original could show an array of links.
But, a simple fix to the UI would go a long way to preventing user confusion when clicking a link that seems dead.