private List<String> allSourceRefDescriptions() {
        return searchChainResolver.allTopLevelTargets().stream().map(com.yahoo.search.federation.sourceref.Target::searchRefDescription).toList();
    }
The name of the query property containing the source name added to the query to each source by this
container-search/src/main/java/com/yahoo/search/federation/FederationSearcher.java