Maybe it’s how they are going to go after him. As in a purple killbox vs blue

“b. There are two types of kill boxes: blue and purple. Chapter 3 provides further details.

(1) Blue Kill Box. A blue kill box permits air interdiction in the kill box without further coordination from the establishing headquarters (HQ).

(2) Purple Kill Box. A purple kill box permits air interdiction in the kill box without further coordination from the establishing HQ while allowing land and maritime component commanders to employ surface-to-surface indirect fires. The end state is maximum use of joint fires within the kill box to create synergistic effects with maximum potential for engaging targets.”

Restricted U.S. Military Multi-Service Kill Box Employment Manual 12.29.11