The lower tether anchorage points can mainly be used in combination with the car's seatbelt to secure certain rearward-facing child restraints.

Child restraints installed on any rear seat or the front passenger seat can use the anchorage points.
Tip
Anchorage points for the rear seats

The lower tether anchorage points for the rear seats can be found at the back of the floor rails of the seats in front.
Anchorage points for the front seat

The lower tether anchorage points for the front passenger seat are located on the sides of the seat's footwell.
Note
Manufacturer's instructions
When using anchorage points, always follow the instructions from the manufacturer of the child restraint.