Looked Roosian, had an air inlet spike like a Mig 21. Twin engines, stacked on on top of the other. Wings vaguely reminded me of Mig 17 or 19. Two seat, side by side under a single canopy.
It was in use to demonstrate some upper atmosphere stuff, purported to be well over Mach capable.
No pics, caught sight of it in the doctors waiting room on TV.
Any ideers?