Panel appeared inside timeline

Hello,

So i'm new to adobe animate, and working on a school project. I was trying to edit some keyframes inside the timeline when suddenly i pressed too long on the bottom of a layer, and this panel appeared on the bottom of it. I do not know what it is called. How do i get rid of it, and how did it appear in the first place?
Becouse i don't know what it is called i do not know how i can find a sollution.