It's "Savlar", not Saviar (Sounds like a GRIMDARK Russian Delicacy

)
http://wh40k.lexicanum.com/wiki/Savlar_Chem_Dogs
There's a Lexicanum link to the Savlar
IG page, but there doesn't seem to be an entry for Savlar itself. And if Lexicanum doesn't have one, it's unlikely anyone will.