Possible Clues:

• Like old software embedded in retrograde safety cage locks
• It's passed on, say, in diaphanous wrapping
• What's left, say, delicate outlines
• What's coming to you
• Gift left in a will
• Something left back in empty cage by lion?
• What's handed on in fancy cage left upside down
• Firstborn's heritage
• Something left (or left unfinished!)
• Bequest in a will