What is a diplomatic passport & what are its privileges?

Diplomatic passports, like the one used by Prajwal Revanna to escape to Germany, are given to government-appointed people travelling abroad, A/B branch IFS officers, family members of IFS/MEA officers, etc. It's valid for five years and comes with certain privileges, including immunity from arrest and legal proceedings abroad. Indian diplomatic passport holders can travel visa-free to 34 nations.