This module adds a new "History" tab on your Feeds import page at /import/[your_import_name].
This tab recaps every action that has been made since the first import to the last (content creations/updates/deletions) and allows you to bulk delete an import (revisions need to be activated for your content) instead of using the "Clear content" tab which deletes every single node imported through the importer.
This module is experimental and should not be used in production before thorough testing, use at your own risk.