style id “generate-style-inline-css” in head — where does it come from?

I’m finding it a little tricky to override the styles that are in the head element of my Generatepress site. Styles like

.sticky-enabled .main-navigation.is_stuck {
    box-shadow: 0 2px 2px -2px rgba(0, 0, 0, .2);
}

That one is on line 56 of the index, which when I look, are in a style tag with id generate-style-inline-css.
Where do those come from? Sometimes I find them in the Customize settings so I can change them there. But if, for example, I don’t want a box-shadow on my sticky navigation, I have to override it with a more specific declaration in my child theme, because I can’t find any setting anywhere where I’ve set a box shadow on the sticky navigation.

So I just want to know where they come from, so I can maybe find the spot where I can change the setting at the source, if you understand what I mean.

Thanks! Loving this theme and GB pro. I’ve built wordpress themes from scratch using Roots/Sage for years now, but this is soooo much easier and much faster. The guys at Perfmatters recommended it.