FileReference triggerDistributionOfApplicationPackage() {
            FileReference fileReference = fileRegistry.addApplicationPackage();
            FileDistribution fileDistribution = fileDistributionFactory.createFileDistribution();
            log.log(Level.FINE, () -> "Ask other config servers to download application package for " +
                    applicationId + " (" + fileReference + ")");
            ConfigServerSpec.fromConfig(configserverConfig)
                      .stream()
                      .filter(spec -> !spec.getHostName().equals(HostName.getLocalhost()))
                      .forEach(spec -> fileDistribution.triggerDownload(spec.getHostName(), spec.getConfigServerPort(), Set.of(fileReference)));

            checkTimeout("startDistributionOfApplicationPackage");
            return fileReference;
        }
The version of Vespa to build first when there are several config models, empty if latest version should be built first
configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionPreparer.java