H1B Visa information from previous employer?

[Jacobdeiter]

I got my H1B visa thru my current employer and worked in USA for 3 years. But my visa got denied couple of times so I moved back to India. Now I am planning to quit the current employer and apply for a cap exempted H1B petition thru a new employer. In future, if I ask my current employer about my H1B details they may not provide it. So

1. What are the information related to my previous H1B petition needed when apply for new H1B petition with new employer?