When I was editing a note type, before adding any notes, this box popped up when I created a new card type:
I brushed it off as unnecessary but harmless. I just came across a post on Reddit, however, where a user was confused by it. I suggest not showing “This will create X cards.” unless X is nonzero.
Edit: Also, note that the left-edge of “Yes” is cut off on the button. (I’m not sure what version of Anki this is from, I took it from the Reddit post—perhaps this has been fixed recently.)