Radar contact speed in TAS or CAS?

[bob123]

I would have though the radar would give a target’s speed in TAS because it simply records the difference in displacement over time?

But from this image here it seems clear that it displays CAS (target speed is 290 from radar, my speed is 282 CAS or 391 TAS, for the -10 closure rate to be correct the radar must output CAS)

is this correct?

[Corsair]

Target speed is a CAS, to be able to evaluate target’s maneuvering capacity.
However, closure velocity is given in true speed.