I remmeber a blog post referred to this but I can’t find it again?
I think this feature you flip a component and set a top/bottom variant anchor or sometihng?
You do not need to set any anchors. If the component is vertically flipped the top anchor will automatically function as the bottom anchor, and vice versa.
Oh I see. When I use circumflex in caron or vice verse I rotate usually but will have to add an anchor in those glyphs. I thought maybe there was a clever way around it 
Well, those are marks, and they do not have top and bottom anchors, but _top and top.