It’s either dried apricot or dried plum, I am unclear on the translation or if it has an exact western equivalent. The Indian words I’ve heard used are aloo bukhara, jardaloo / zardalu, and so on. Which translate to dried plum and dried apricot variously depending on where one looks.
There are always a few in commercial “Bombay biryani” masala packets.
(As you mention Parsi biryani, I was informed by someone Parsi either here or on Chowhound that Parsi wedding biryani is made by Muslim caterers, though the rest of the bhonu is from Parsi caterers.)
From my pantry (stocked solely for biryani):
Here is a picture of the residual pit that might be encountered (the flesh having melted away into the masala) — there are only a few pits in a entire pot, so not everyone might find one.
