TMS320F28377D: Reliability data - MTTF/FIT

Part Number: TMS320F28377D

I found these data from the calculator (https://www.ti.com/quality/docs/estimator.tsp?opn=TMS320F28377DZWTQ&cpn=&partNumber=F28377#resultstable)

My questions are:

1. What percent of the CLK these tests were conducted with?
2. The "Usage temp (C)" means the junction temperature?
3. The "Test temp (C)" means the ambient temperature?

Thanks,