What to know

• MK-84 is among the most destructive munitions in Western military arsenals. Its explosion sends large metal fragments in every direction for thousands of feet, ripping through metal and thick concrete.S1
• The $2.8 billion package includes 40,000 of the bombs, made up of 20,000 Mk84s and 20,000 BLU-117s, sources aware of the developments saidS2
• The 2,000-pound bombs have multiple variants, with some designed to penetrate deep, underground targets while others detonate above ground and cause widespread damage.S3