The manufacturing category is meant to apply to any post about when your KiCad files are complete and you're ready to send off to get made. Also it could be questions about assembly services or integrating your board into a larger product.
- Details about an entire build or product should go in the "Projects" category
- Questions about how to create a certain feature for manufacturing (mouse bites, scoring) should go in the "Layout" category.
- Questions about the generation of gerbers should go in the Gerbers (GerbView) category
- Questions about output parameters for a particular board house can go in this "Manufacturing" category