weired packages policy

[Hans <hans.ullrich@loop.de>]

Hello list,
from time to time I discover packages, which are in stable and sid, but NOT in 
testing. This looks weired for me, as packages, which are in sid, should move 
to testing and then to sid.

This happens also with packages, which are already in stable, suddenly 
disappear in testing, but stay in sid. Then, after some time, these packages  
reappear again testing, 

For example, the package "klamav" is such a case.

I do not quite understand the policy and logic of this.

Maybe someone can enlighten me.

Best regards

Hans