Question: How to disable scrollbar "minimap"

[Jessy Williams]

I'm looking to disable what I think might be a relatively new feature. iTerm2 seems to have some sort of scrollbar minimap. My fish prompt is blue, which each of these lines seem to represent. At times the output of my terminal is other colours like red and yellow which also seem to be captured. The only way I can figure out to hide it is disabling the scrollbar altogether, which isn't ideal. Wondering if anyone has any idea what this feature is called or whether it's possible to disable?

Thanks!