What is the difference between the two boost::adaptors functions sliced and copied?

Looking at the code, one can see that copied uses sliced, but I am not sure if there is a subtle difference.

Maybe it could be explained in the docs.

Moreover, the docs say that sliced returns "make_range(rng, n, m)", but I could not find the documentation for make_range (and only found a function with this name in the range_detail namespace, but which does not correspond).

Thanks!