public List<ApplicationId> activeApplications() {
        return curator.getChildren(applicationsPath).stream()
                      .sorted()
                      .map(ApplicationId::fromSerializedForm)
                      .filter(id -> activeSessionOf(id).isPresent())
                      .toList();
    }
List the active applications of a tenant in this config server.

@return a list of {@link ApplicationId}s that are active.
configserver/src/main/java/com/yahoo/vespa/config/server/application/ApplicationCuratorDatabase.java