I found the tool: Find lowest diagnostic rank (Galaxy Version 1.0.1). The exact column descriptions are on the tool form under the Example section. In short, these are taxonomic assignments.
Please note that this tool is deprecated (as are a few other tools in use). If you want to upgrade your methods/tools to the current ones covered in the Galaxy Tutorials, please see Megatenomics under the Galaxy Training Network (GTN) tutorials: https://galaxyproject.org/learn/
Thanks! Jen, Galaxy team