I never even heard of this. I kept thinking they’re spelling magnesium wrong.
I see the Manganese in my Glucosamoine/Chon — with MSM 87%
and its in my Calcium Citrate 50%
so it appears to be in my diet if I take those each day
google Periodic Table and you can see how manganese and magnesium are different, plus a lot of other stuff you might find interesting.