It is loosely copied from (Nazi Germany) Alexander Lippish’s small delta-winged glider prototype built during WW2.More “napkin-waffe” than OTL.
The DM-1 glider was built of steel tubing and plywood. They intended to use it to explore low-speed handling of the (projected) P.12A ram-jet interceptor. No P.12A was built.
Post war one went to the USA and was tested in NACA’s full-sized wind tunnel. NACA experimented with a variety of leading edge, canopy and fin configurations.
Lippish also sketched dozens of other delta and flying wing airplanes - during WW2 - 19 of which are illustrated on www.luft46.com
After the war Lippish moved to the USA and helped Convair design a variety of delta-winged jets.