org-kill-is-subtree-p

org-kill-is-subtree-p is a compiled Lisp function in `org.el'.

(org-kill-is-subtree-p &optional TXT)

Check if the current kill is an outline subtree, or a set of trees.
Returns nil if kill does not start with a headline, or if the first
headline level is not the largest headline level in the tree.
So this will actually accept several entries of equal levels as well,
which is OK for `org-paste-subtree'.
If optional TXT is given, check this string instead of the current kill.