My first post here so please be kind

I noticed 'KNIFE71', a USAF V22 flying the racetrack around Hereford for a few hours today (11th May). Just to satisfy my sheer curiosity, does anybody know what it may be up to? In my very limited knowledge, I think squawk 0033 may suggest parachuting? But if so, flying around for hours in the hold seems different.
https://tar1090.adsbexchange.com/?icao= ... 2020-05-11

Stay safe!