Oil Tank Breather Tower

[Nourish]

I pinched the picture below from an earlier posting from this forum.
On the Star Twins tank below the breather is unlike the std twins tank
Does any one know why they altered it and what's inside?
Oh - and does the oil tank on the S/F go back further than the std rigid frame tank to hold more oil?

[Nourish]

But then there's this tank too

[Bsalloyd]

I believe the tank pictured is the one BSA used on the A7 twin race bikes for Daytona and possibly others.

[Nourish]

Here's a Daytona replica I believe, and a real one

[BSARoadRocket]

Is there any chance I could see some photos of the back side of the red oil tank?   I need an oil tank like this and I figure the only way to get one is to make it.