Handlebars filled with cork
 

I was looking at an old steel set of nitto olympiade drop bars and I noticed that there seems to be cork inside the tube. Whats the purpose of this, is this common? obviously I don't have reason to be shining a flashlight down a set of handlebars often so i'm not sure if this is stock or elsewise

they used to use cork to plug the ends of the tubing on the bars to prevent puncture wounds. someone probably didn't remove it.