* comment: Field name for sequence number in the index.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getIndexFieldSeqNo();

    /**
     * Get the value for the key 'index.field.primary_term'. <br>
     * The value is, e.g. _primary_term <br>
     * comment: Field name for primary term in the index.