Toro Rosso were one of the teams to start the season with the inboard-loaded front wing, thus they use the endplate in a different way to push airflow out around the front tyre.
Toro Rosso’s new footplate area is revised to make the vortices stronger.
As free-stream air rolls under the footplate from the outside, pulled in by the low pressure created under the wing, it’s spun into a vortex by the arched footplate shape.
These of sort of treatments are typical of Toro Rosso who lead the trend in many detail areas of aerodynamics.