SplitView toggle button

I've successfully created a SplitView when viewing on the iPad by
Code Block
NavigationView { 
MasterView()
DetailView()
}

but I've noticed a toggle button on the top left when the iPad is in landscape mode, I would like to know if there's any way to either change the button color or hide it.
That is new for iPadOS 14 and is automatically put there by SwiftUI. I don’t think you can hide it but changing the accent colour should change the button colour.
SplitView toggle button
 
 
Q