It is a global discount applied to the total amount of the quotation. It is set in the section Amounts, discounts and special terms.
Quotation line item discounts are added to the bottom line discount.
The total amount of these discounts is shown in the Amounts, discounts and special terms section of the quotation, in the fields Discount total and Discount total (%).
José is satisfied with Linda's explanation and rushes to gather his team to show them how to apply discounts.