Hi Rick, I also have a Kaskara with this mark, but I have no idea what it signifies.
The sword was purchased by me last year in a village outside Port Sudan. It was a very exciting experience to say the least. I first found a guy selling a sword or two in the market in the Town Centre, but his asking prices were ludicrous. After making some friends and asking around I was advised to travel to a village about 20 min out of town where there is a market operated by the Beja Tribesmen. After looking around at a few camel saddles and other Beja neccessities, I showed some interest in a couple of 'Saif,' I was soon surrounded by 40 or 50 men and boys waving swords in my face
and crowding in all around me, trying to sell of course.
I didn't know much of anything about Kaskara but had researched a little about what would be a good souvenir from Sudan just before I left for Sudan.
Most of the Swords were rather new or if old were in poor shape, but I believe they had better examples that were put away and not for sell. I bargained hard and bought a couple of swords and all sales and cash had to pass through a village headman.
I became very fascinated with these Beja and their Arms and Armour and have done a lot of reading on this website and other sources. I have even bought a few other beja items online since then. I hope to return to Sudan oneday. Sorry I can't offer any serious research, just ancedotes
J Jambu