The Unstructured Data Transformation (UDT) calls a Data Transformation service from a PowerCenter session.
Data Transformation is the application that transforms the unstructured and semi-structured file formats. You can pass data from the Unstructured Data transformation to a Data Transformation service, transform the data, and return the transformed data to the pipeline. The Unstructured Data transformation can be an active or passive transformation.
More at: Unstructured Data Transformation
Also, check if you have any PowerCenter mapping which has an "Unstructured Data Transformation" (UDT) in it.
To use UDT, it needs Unstructured Data License. Below is one of the UDT transformation configured in the mapping.
could you please give an example? Your description is too unspecific to make anything useful out of it (at least for me).