It's called 'detonation cord' or 'primer cord.' I believe there is a brand called PrimaCord but I'm not sure if the military still buys it. I'm sure it's still around for mining, etc. Cord is more reliable than old timey fuse.
I didn't normally deal with 'bang stuff' every day but sometimes I did. The way the engineers explained it, it carries a good but small shock wave or 'over pressure' all the way
almost to the end. The wave ends just before the cut end. The wave actually pushes out a little of the packed powdery/crystal explosive when it gets there, and dies off. You want the wave to go all the way through and actually surround the cap or charge you want to set off. You use more cord than the actual length to get a good shock wave. If you don't plan on any more shots before the roll expires, you normally just set it off rather than let it go bad and have to dispose of any potential hazmat.
THE GOOD part of the story...in '94 I was on a testing range standing by with a couple of walkie talkies and an ambulance (sadly, Amber Lamps wasn't there or it would not have been such a boring week.) At the end of the week, the OIC (officer in charge) asked me to stay an extra half hour on that Friday and promised I would have fun. We had to get rid of some bang stuff expiring that month. IIRC, it was 4 lbs of TNT, two half rolls of det cord (something like 100 meters) and over 30 lbs of C-4
He let me set it all off. We used wire > electric cap > good det cord > crimp cap on the end of three winds of the other end of det cord > one 1/4 lb block of fresh TNT in the center of the pile of expired stuff. It was all in about a 6 ft. deep pit, all sitting on top of a 5 ft piece of I beam. The beam looked like some kind of twisted modern art after. To this day I have a
reverent respect for explosives.