Extracts the meta information key, value pairs of documents. It can be specified whether the documents are appended or not and if duplicate documents in the input table are ignored and meta information is extracted only for distinct documents. Furthermore keys can be specified for which the key value pairs are extracted. Since there may be several key, value pair for each document original row ids can not be kept. For each key, value pair of a document a row in the output table exists. The output table contains at least two columns, one with the keys and another with the values. A third column containing the documents itself is appended if specified in the dialog. Documents that are missing or that do not contain selected keys, or any keys at all will be omitted.