General Mysterious Plate

[RauchRauch]

I was sanding off rust from the van's floor today - Ducato II 2.8 - and noticed this.
Next to the right wheel arch.
I was about to crank it off with a crowbar but i realised that it's tack welded in!
I might still remove but before then: what is it!?!
It's actually the bit with the most rust in the whole van, all the rest is superficial.

 

[jackwhoo]

To me it looks like fitted at factory during construction. Leave it in place it's there for a reason .

 

[jackwhoo]

Look under van where plate is and you may find it's purpose.

 

[RauchRauch]

I can't access it from the bottom. I'd like to leave it there but it's so rusty even underneath, and looks like it's covering a hole