We got this stainless steel mixing bowl at a "dollar store" - it cost $4 (not long afterward, we saw the very same size and type of bowl for $10 at Canadian Tire). But we didn't get the bowl for mixing. After reading Lionel Vatinet's book, A Passion For Bread, we got it to use as a steam chamber for baking bread. (A roasting pan works. So does a casserole dish.)
The bowl holds 5 quarts/ 4.55 liters.
It fits, leaving plenty of room around the edges, over a shaped and proofed boule. (For display purposes, I took the photo on the counter rather than into the oven so as not to lose heat unnecessarily.)
The first experiment with the bowl, we did not use the stone in the oven and produced unintentionally flat bread. After baking, it was virtually the same size. (The other loaf was put into a loaf pan and baked normally.)
This is the 2nd try a week or so later, with the bread baked on a parchment lined pizza pan. This was maybe a fraction better but still on the flat side.