I found this in a bengal breeder's website. The part in bold IMO is not the current egyptian mau but an unknown cat that resembled the mau and was used in mau and bengal breedings. So that is where the glitter comes from but is not the standard for the egyptian maus
The genetics was indeed challenging! Early domestic partners of the original ALC males were of unknown heritage and brought a wide range of recessive genes to the crosses, such as long hair, dilute colors, solids, colour point pattern, and the classic tabby pattern. But when the latter met with the leopard spots, the result was a dramatic "smearing" of the spots into odd, startling patterns of black, rust, and light tan combinations. Kittens looked like richly colored Easter eggs! And each kitten was unique! They were called "marbles", were included in the Bengal registry, and were given their own classes at the shows. One of the early genetic contributors to the new breed was a young domestic male from New Delhi, India (Millwood Tory of Delhi), who brought gorgeous emerald green eyes, a spotted coat without stripes, glistening, thick fur (now called "glittered pelt, and a "hot" orange colour.
These characteristics were unknown in the American cat gene pool before that. Early Bengals were carefully bred for sweet temperaments and also exhibited intelligence and unique behaviors tracing back to the wild a
I looked at some other bengal websites. Correct me if I'm wrong - but the "glitter" seems to be the more reddish/orangy base color in the browns. Is that right?