Based on what I've seen of this form from your other posts, it's likely that this column is associated to the Repeating Section Control you have on your form.
To verify this, open your Form in the Designer:
And select the Repeating Section by clicking on it:
Then look at the top Ribbon to see if there is a value in the "Connected to" drop down (NOTE: I don't have this test control connected to anything!):
Whichever Column you see in this position is where all of the XML is going for the repeating section.
Additional Information: Like all Form Controls, Repeating Sections have a "value". It's just that because they contain (or at least *can* contain) a LOT of values, the value that they spit out is structured XML.
I hope that this helps to clear up what's going on.