Emacs 28.1 Orgmode 9.5.2 (but discovered already 2020-01-20)
When pasting a subtree (of whichever level) with org-paste-subtree at any position (can be an empty line or a line with a header prefix, e.g. "*** "), always an empty line is inserted above the inserted subtree.
I would expect no new line to be inserted, and I think this was the behaviour before I noticed this.
The value of "org-blank-before-new-entry" is "((heading) (plain-list-item))".