Trust me, it isn't attached to anything special!
I got the stem from a friend in the nineties when I was putting an old Pallisade Trail back together and it has been on the bike ever since. I would be happy to swap it for a comparable stem of the right vintage for my Marin Bear Valley project. The current Marin stem has no rise and therefore if someone wants this Breezer stem and they can find a 1" black quill stem with 10-15 deg rise and approx 120mm c-to-c with cable roller (prefered) then I will happily swap.
Start digging gents.....