In 1987 Mastertronic created a game for the ZX Spectrum called Rescue. Never seen it, but caught this easter egg on a page describing the game.
On the main title screen, which I assume this is what they mean
If you press BREAK, you get the following screen
I am assuming that this is because Mastertronic used the Einstein as a tool to program the ZX Spectrum games, like other software houses of the 80s! The programmers either had some spare bytes left to mess with and pay homage, or this is some sort of worm hole into their development environment

Gonna have to fire up my speccy emulator and run the TZX/TAP file and see if it is true!

Mike.