Follow up to confusion about terms in backpropagation calculation

Here is the screenshot of the part I'm referring to: https://imgur.com/a/GRQEtiw   The following is the text from the original question: On the Backpropagation Mathematics tab, it goes into the derivation of the update rule for the output layer. Right before section 5, I was wondering about how it got from (y_j – t_j)y_j(1 – y_j)h_i to \delta_j h_i (not sure if we can input equations here). I think I’m unclear as to how \delta_j is defined, I assumed it was the error y_j – t_j, but then there’s an extra y_j(1 – y_j). Thanks!