to give the first useful answer, the russian big muff has different values in the tonestack, coupling caps, resistors.
most prominent are a slightly different tonestack and sound changes due to the different coupling caps.
usually, the triangle (nyc) big muff, the russian (or green) big muff and stock big muff are distinguished.
and, btw, @kaputsport, somebody already had the idea to name a pedal "cameltoe" long ago, a certain mister huge aka way huge electronics.
to anybody with further interest, i warmly recommend to google the different schematics.
cheers,
lowstar