Yes, I mean something else. :)  When "--close-branch"-ing or merging back to "default" are closed and hidden in the branch list, but still present in the revision tree, and you get warnings if you try to create a new branch later with the same name.  In Git they are just <i>gone</i>, as if they were never created. (Note that you have plenty of opportunity to restore them before garbage collection if you deleted one by accident.)