I recently inherited a D7 site and in the discovery process found a slew of database tables with a "dr_" prefix. They seem redundant and I'm inclined to whack them during the clean up process, but am hesitant because I don't know what the hell they are. I thought it was Backup and Migrate or Features, but it doesn't seem to be.

I've done a bit of research, but cannot, for the life of me, figure out where these entries come from. Does this sound familiar to anyone?
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