public ArchiveUris readArchiveUris() {
        return read(archiveUrisPath, ArchiveUriSerializer::fromJson).orElseGet(() -> new ArchiveUris(Map.of(), Map.of()));
    }
Returns the instant after which a firmware check is required, if any.
node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/CuratorDb.java