I was using a Hilti SDS drill yesterday, Hilti put fantastic lead on their gear. Feels like silicone and it doesn't have any memory or get tangled.
I bought some silicone lead from Temu to try, it's better than the stuff that came on my Metabo grinder but it's no better than the H07 I normally use.
The Temu stuff has random coloured cores so isn't exactly ce marked either.
Cable specifcations are standardised and enumerated, and it is unlikely Hilti are using something proprietary. If you could find the cable designation, we might find a source for it.
Your mention of silicone reminds me of Antex soldering irons - they offer a silicone cable option, for both heat and flexibility reasons.