End data folder location

So I have asked a question how to find the End city if I have updated my game from 1.8 to 1.9 and already killed the Ender dragon and generated the End island in 1.8 (see here). I got an answer from Antoine Hejlík (see in link) and he recommended to delete the files that contain the End data, so I can generate the End again in 1.9. I have already made a backup, but I dont know where can these files be found I just know it is in .minecraft/saves/myworld/???.

I would be glad if someone knew what should replace the ??? above.