So basacly that bug allows you to wear the Minecon 2019 cape whitout the texture pack and also the pan cape so basacly ppl roam around with one cape that normally you shouldn't be able to unless you have the pack and the other that used to be a glitch in beta.

Note:(I have personnaly the texture pack of the minecon but i know this bcuz my friend used an acc whitout having the texture pack and got the minecon with it)