What is static line training, and why is it included in a military

What is static line training, and why is it included in a military freefall operations package - Skydive Perris

File:Marines, soldiers conduct static-line airborne training 130317-M-FD301-024.jpg - Wikimedia Commons

Does the military count static line jumps done with civilian companies or veteran jump groups onto a paratroopers military jump log? - Quora

UNITAS: Recon Low Level Static Line Jump

NATO allies conduct joint drop training - Kaiserslautern American

Airborne Rangers test new civilian rucksack designed for parachute operations

Military Static Line Jump

Mock door - 10th Special Forces Group - Airborne

My Mom Does Not Like It': Inside A Nighttime 82nd Airborne Jump as Troops Wait to Deploy