These files can be used to help debug problems with mg and mgpp. An example of running mgpp_passes is as follows:

cat doc-for-text-pass.txt | mg[pp]_passes -f FILENAME -T1

The T1 pass will generate a FILENAME.tsd file. In order to run the T2 pass you need a FILENAME.td file which can be created using:

mg[pp]_compression_dict -f FILENAME