Exhaust stud removal help.. see pic

I need to preface this story with “I’m a total rookie when it comes to working on cars.” I put headers on my Dart and the drivers side rear was leaking real bad. I lived with it for a couple of weeks, but I couldn’t stand the noise any longer so I decided to fix it today. When I pulled the headers back I noticed a little stud that the flange of the header was hitting (see pics below). I can not believe I didn’t notice it when I installed them. What is this stud for? I assume I can remove it. Is a hacksaw blade the best way? There is no room to maneuver the header that much.
Thanks,
Kris