A repository is one brand page at one address, such as gitbrand.com/north. It holds that brand’s logos, colors, fonts, resources and FAQ, and it has one access level: public, password-protected or member-only. Changing the access level does not change the link.
A second brand is a second repository. A sub-brand with its own logo and palette is usually a repository too, though many teams keep sub-brand marks as extra logo variants inside the parent repository. Cloning a repository you are a member of creates a new private draft that counts toward the limit.
The Free plan allows five. Repositories over the limit stay readable and shareable; you just cannot create more until you archive one or move to Premium.