Typo with backprop parameter?

It was supposed to be δL/w [1]? Seemed confusing at the very end. I understand that he mentions that other parameters will be treated in a similar fashion (symmetrically) so he was focusing on this backprop demonstration.
Is this just my misunderstanding or is this a typographical error?
Thank you.

Hello, @Paul_Hume I think this must be a typo. Let me forward it to our team for review. Thank you for reporting. If you come across any other error feel free to open a new topic