Front derailleur frame braze on?
I have a 90's era Concorde that I am building for my first build. I'm looking to put the front derailleur on, but there is some sort of braze on hanger thing in the way on the seat tube. It is slightly curved and maybe and inch squared with a slot in the middle. It seems to be right in the way for placing the derailleur where it should be. The derailleur is a 2000 shimano 105 9 spd. Is there some way to alter my derailleur so that it attaches? Does this item need to be removed? Can that be done easily? Or do i need some other derailleur?