What's the difference between "deductible refund" and "deductible buy-back"?

Understanding the differences between a deductible refund insurance and a deductible buy-back option

Deductible refund is an insurance product that we offer you to take out when you book your vehicle, after you have chosen your vehicle. See below:

In the event of a claim, you pay the excess to the rental company, which is then reimbursed by the insurance company.

Deductible buy-back is a product offered by rental companies when you pick up your vehicle, and the deductible is effectively reduced to zero. In the event of a claim, you don't have to pay the excess.