The android is at Mario's village. Go to the library and click the bottom placed on the background, this will open a new location (Lab) at the library. If you don't see it right away after clicking the button, go out of the library and back into it.
Thanks will try
Nope there is no secret button pop up in library for me
Hello there, is on the background, is not a "pop-up"
Bro still active to answer that
