The directory /metadata-catalogue contains two sub-directories, /metadata-descriptions and /metadata-tools. The metadata descriptions that contain information on \ the data located in the MLDB are prepared with the metadata editor available in the sub-directory metadata-tools. Metadata descriptions are located in the sub-directories that are named according to the names of languages. Metadata descriptions can be openend with the metadata browser available in the sub-directory /metadata-tools. Structurally the metadata descriptions are xml-files. Metadata descriptions will also be publicly open.