I thought so too. Jacobs certainly are a Tier 1 giant, though...

I thought so too.

Jacobs certainly are a Tier 1 giant, though not strictly a pure defense contractor. More industrial conglomerate with defence activities, reflected in their position on the list.

Mind you #35 is nothing to sneeze about.

And what do Jacobs do?

Jacobs is the prime contractor for the Missile Defense Agency's (MDA's) Integrated Research & Development for Enterprise Solutions (IRES) contract, providing integrated solutions to support the concurrent test, training and operations of our nation's missile defense systems.

Reading between the lines, I can see integrated solutions to support the concurrent testing, training and operations of missile defence systems requiring 3D digital twins for starters...

https://www.jacobsmissiledefense.com/