These are default kill chain icons. The icon names map as defined below:
Recon = Search99 OR Magnifier12
weaponization = toolbox3
delivery = logistics3
exploitation = open125
installation = install1
Command and Control = social12
Actions on Objectives = War13
Recon = Search99 OR Magnifier12
weaponization = toolbox3
delivery = logistics3
exploitation = open125
Command and Control = social12
Persistence / Lateral Movement = Circular138
Actions on Objectives = War13
Exfiltration = money194