It is not a myth - it did once exist and it came in a plastic wide mouth jar that you could dip your sponge in for just the right amount rather than the liquid form spilling more than you need onto the floor or your soaking your tack with water.
It was wonderful at cleaning tack. IMO much better than Fiebings saddle soap.
I just got off the phone after being told that the product was unavailable due to low demand.
The customer service number is 1-800.468-6502.
Let’s demand it back.