"Next 90 days of subscription for free" offer, while canceling Photography Plan

Hello everyone,
I was cancelling my Photography Plan (20 GB) because I’m close to the renewal date, and right before finishing the process I was offered 90 days for free. The problem is that the page only says “the next 90 days will be free” and “your price for those 90 days will be €0.00”.

Does this mean that accepting the offer will also renew the subscription for a full year, so that I would have to pay for the remaining 9 months after the free 90 days?

My idea was to accept the offer, use the plan for those 90 days, and then cancel before the free period ends, but I’m worried I might be charged an early-cancellation fee.

Does anyone know the terms of this offer?
Thanks!