Via cxxeditor@:

Finally, I noted a very minor typographical issue: There seems to be
a space missing after "see" in the index entry for
"conditionally-supported behavior". I also suspect there shouldn't be a
page entry here, given that it's a cross-reference to another entry.
(Besides, the page number is wrong.) [Hmmm; I now see this entry is
generated via an \indexdefn macro call; perhaps it should be an
\indextext call instead?]