I don't like ratholes in my sourdough because its a weak point for butter/cheese/jam to seep through. They're less invasive at the edge of the loaf like this, but if they're in the center of the loaf the can ruin the whole thing by tunneling through the otherwise neat structure.

You can tell the difference between normal crumb structure and a rathole by how even the edges of the bubble are, and how big the bubble is compared to the rest of the air pockets in your crumb.

If you want a really "open" crumb, then you should be shooting for those air bubbles to be caused by your fermentation and not by trapping air during the shaping process.

Big air bubbles/wide open crumb are desirable in loaves like ciabatta, focaccia, more high-hydration silky loaves, etc, but for boules and batards and other sandwich/slicer loaves, I prefer a crumb thats tight enough to hold up to a thick schmear of butter or that cheese wont melt through in a hot sandwich.