A DLT file contains a dataset created by the DELTA System, an integrated set of programs used for recording taxonomic descriptions in the DELTA format (Description Language for Taxonomy). It contains taxonomic data such as leaf length and flower color that's organized through DELTA. DLT files are typically used for saving backups of data.

You can open DLT files with DELTA Editor, which is a tool included with the open source DELTA system. You can also create DLT files in DELTA Editor. To create a DLT file in DELTA Editor, follow these steps: Select File → New Dataset. Enter in your data, then Select File → Save Dataset. Choose your save location (you can create a new folder for the DLT file if you want), name your file, and click Save. Changes made to the database are not automatically saved. Instead, the DLT file must be saved by selecting File → Save or Save As. NOTE: IB-CAS is short for the Institute of Botany, Chinese Academy of Sciences.