The final in my trilogy of spurious parts

Hello T World

I pulled down two T radiators

I did not notice the size of this bottom tank till I went to make one from the two. All I can say is I did not see it because I was looking right at it

Sorry I made a picturing error. What you cant see in the two pictures it the support bar does not run side to side just at both ends.

My question is what is it? Spurious or a Canadian oddity found in Australia