Sorry guys, I posted in wrong forum, should be in Branson (2515H)
Now, that's odd, little plastic tank right next to the left foot rest (and probably extending under it).
That isn't where I would have immediately thought to put it. However, my guess it is extremely easy to fill. Many of the smaller tractors the tanks are frequently filled with a 5 gallon gas can, and it is always a pain to lift it up to the cowl or other tanks in awkward places.
If you lose some diesel, it won't be in a place that will hurt the tractor.
You're above the front axle, so hopefully not dragging on anything.
It doesn't look like a place one would step or kick a lot.
My guess is the fuel pipe pipe to the engine is in the top and relatively protected.
The front end loader shouldn't interfere.
And the new poly tanks are quite tough.
If I was building it, I'd have put a skid plate in front of it and under it, but it probably isn't needed.