Human rights describes the individuals that the rights pertain to, no? So those human rights could either be based in legality or in morality, which wouldn't always align. People may also have different beliefs about which human rights are morally justified and which ones aren't. If there's a third kind of human right that isn't based on what's legal or what's believed to be (or, fundamentally is) moral, then what's it based in?

Inherent to the human condition is interesting, but isn't that still a moral stance/belief? Even if you argue that it's objectively moral (and if you don't believe in moral subjectivism/moral relativism) or objectively the right thing for humans to have rights based on the kind of beings that they are, how is that separate from morality? As far as I know when someone says "this is a human right" they're usually asserting that they believe it's morally correct for humans to have a certain right, and that it would be wrong to violate that right. Occasionally someone says "this is a legally protected human right" to emphasise that it's a legal right enforced by law. I'm not sure by what metric rights could be ascribed or theorised conceptually to apply to certain individuals, if not law or ethics.

For example, you could say that the law did violate the enslaved's moral human rights, by assigning other humans a legal right to own them, which many at the time would have also believed was their moral right, even if we don't agree with that today or assert as being objectively immoral. If their human right to not be enslaved wasn't legal or moral, I don't see what the third option could be.