after googling :
The towbar is equipped with the "Fix4Bike" system. It allows the installation of future accessories specially prepared for "Fix4Bike"
https://accessories.volvocars.com/en...CC-516356/2019
https://www.thule.com/en-lt/bike-rac...t-f-3-_-966500
so just an extra 'thing' to secure cycle racks