  The OPE treatment that has been so successful in describing inclusive $\bar B
\to l \bar \nu X_c$ decays yields sum rules (in particular the Uraltsev sum
rule and its higher moments) implying the dominance of the $P$ wave $j_q = 3/2$
charm states in $X_c$ over their $j_q=1/2$ counterparts. This prediction is
supported by other general arguments as well as quark model calculations, which
illustrate the OPE results, and by preliminary lattice findings. Its failure
would indicate a significant limitation in our theoretical understanding of
$\bar B \to l \bar \nu X_c$. Some experimental issues have been clarified since
a preliminary version of this note had appeared, yet the verdict on the
composition of the final states {\em beyond} $D$, $D^*$ and the two narrow $j_q
= 3/2$ resonances remains unsettled. Establishing which hadronic configurations
-- $D/D^* + \pi, D/D^* + 2 \pi, ...$ -- contribute, what their quantum numbers
are and their mass distributions will require considerable experimental effort.
We explain the theoretical issues involved and why a better understanding of
them will be of significant value. Having significant contributions from a mass
continuum distribution below 2.5 GeV raises serious theoretical questions for
which we have no good answer. Two lists are given, one with measurements that
need to be done and one with items of theoretical homework. Some of the latter
can be done by employing existing theoretical tools, whereas others need new
ideas.
