AMD were a bit vague. I'd presume they mean Zen 6c. That said, the primary differences between AMD's standard and c cores is cache sizes and density. With density trading spatial efficiency for lowered clock speeds. For the most part, the cores are very similar.
Benefits applying to Zen 6c cores will, mostly, apply to their larger counterparts. So strong gains with Zen 6c should also mean strong gains for Zen 6. AMD's 192-core Zen 5 EPYC CPUs use Zen 5c cores.