It's in the README.txt file that's part of the zip archive. Here's the entire text of the README.txt:
This ZIP archive contains the installation files for the DataUp AddIn
for Excel. This add-in is part of the DataUp Project, whose goal is to
facilitate data management, sharing, and archiving for scientists. For
more information on the DataUp Project, visit http://dataup.cdl.org.
To obtain a copy of the user guide for the add-in, visit