Yep. The paper I use is sized for manga, and it has 'live area' and 'bleed area' and 'border' marked in non-photo blue, which is used to tell the artist which areas will definitely be shown, which will probably be shown, and which might be shown but not on purpose. Text should be confined to the live area - inside the dotted line, while stuff in the bleed area will probably be shown, and goes to the very edge of the page. There's a little bit of a border area, but that's just insurance and I don't include it in the post.
Light blue doesn't photocopy well, and there's a specific shade that photocopies so poorly in black and white that they actually call it non-photo blue. This means it's super easy to remove when printing. However, since I scan the pages instead of photocopying them, the blue is still visible. Technical explanation is technical! XD;