Double Tap lists a 375 H&H with 260 Nosler at 2900 FPS MV.

https://doubletapammo.com/collections/all/products/375-h-h-260gr-nosler-accubond-20rds

I’d believe it if I saw it over a chrono. My experience with DT has been okay, but at least their pistol ammo has slightly wishful reported MVs, at least IME.

I have zero experience hunting big cats, but I wonder if 100 to 200 FPS MV would really matter on a leopard? A 260 gr Accubonds at say 2700 FPS is nothing to dismiss.