Some time in the future there will be carbon black/LOX explosives used: the only forensic traces will be soot and carbon black, not easy to distinguish from other explosion aftereffects.
Why go to something exotic and bulky when there are small, compact and exceptional bang for the buck alternatives? You really want detonation for back/packs not deflagration, which the LOX/carbon gives. For a car bomb, the Kansas City mix is cheaper, more portable and more stable and is a deflagration mix like LOX/Carbon black (which some use as rocket propellants). Plus, the LOX/carbon black mix has been around for a long time and was only used when nitrates were in short supply.
Finally, the last concern of a bomber is worry about the ID of the explosive.
IIRC from Stetbacher's book, LOX/carbon black does not deflagrate, but detonates at 4+ miles/second, as good as RDX.