Ex-Luftwaffe Alphajets

This weekend I was snooping around the Arlington, Washington airport…(alas, outside the fence.)
Aside from a pair of unmarked L-29s and a MiG-21 (I couldn’t see any markings) what got my attention were a pair of very airworthy ex-Luftwaffe Alphajets. (I’m guessing they were ex-German as they had no markings, but they were in the dark green/black paint and had the pointed noses).

I wasn’t aware that any were on the civil register…anyone have details?