This module can help you shed some light into the black box of Feeds and Feeds Tamper.
It takes advantage of Feeds Tamper's extensible plugin architecture and allows you to debug the data being processed in three different ways at any step of the tampering flow.
This plugin allows developers to integrate Latch on his/her Drupal service. Latch is a service that lets end-users add an extra level of security to their online accounts and services.