[DeTomaso] Speaking of coolant tubes - what is this plug for?

[Charles McCall]

This is the stock coolant tube on my GT5-S. Please compare to a
replacement purchased in Stainless Steel that is missing the plug.

What was the plug for? Is there any value in having it cut off and
welded onto the replacement tube?

Please see this photo comparing the two:
http://www.poca.com/index.php/gallery/?g2_itemId=36095

anda  blurry photo of the plug here:
http://www.poca.com/index.php/gallery/?g2_itemId=36098

Thanks!