Perfectly healthy root system with no root rot at all and is exactly what I would expect to see in my pots after harvest.
Root rot will have mushy roots.
50 litre pots are a great size, only growing directly in the ground will allow unimpeded growth.
Congratulations on asking the question, most people quickly lose interest once they harvest their plants and I thought I was the only one to bother with checking the root system after harvest and have been doing so for 25+ years, just to gauge how the plants coped with the pot sizes I have used/tried.
Cheers, Organoman.