The value of number registers can be read directly from xyPerl using the $X->get_reg(#NUMBER) function.
But for named number registers there is no equivalent function.
It would be nice if there would be a $X->get_named_reg(NAME, LEVEL) function (or similarly named function).
Currently you have to use the $X->nnx(NAME, LEVEL, X-register) and then do a $X->get_reg(xNUMBER) in order to access the value stored in a named register.
That is a bit a cumbersome and confusing way for something that should be simple.