What is "field_data_upload" and how do I make the FixInitFiles migrate script work?

I'm back to trying to upgrade to Drupal 7, and I'm confused by what's happening in the migration.

I don't have a field_data_upload table on either the old system or the new, and I can't seem to figure out what would be responsible for that table.

So, what is that field, and what module am I missing (or was I missing on the old D6 site) that provided that table?

I do have files in my issue tracker, but at this point I'm fine with losing them completely, if I can just get the damned thing working at all in Drupal 7 (right now issue content is in the new database and browsable if I hit the node directly or get there from the Drupal new content page, but is not visible or searchable, at all, in the issue tracker).