Not which papers you didn’t read, or which things you got stuck on. Not the title of your supervisor or the uni you did your undergrad at.
Your significant, original contribution matters. What did you do? How did you do it? Why did you do it?
Be prepared to have a conversation in your viva that explores this new, valuable something that you have. Consider what you could do in your preparation to help you explain, explore and share this contribution that you have made.