\initial {\\} As I recall, Arnold and I did that as part of the new texindex, so that backslashes could be properly sorted, etc. It seems semantically correct to me. Trying to treat "{\tt \indexbackslash }" as equivalent to "\" seemed poor design.
(Ultimately, what I really want is for the index files to use @ instead of \ for the escape character, as should have been done from day one, but the new texindex has to get far more widely deployed.) I wonder if there's any way for texindex to output something that is very likely to work with a bundled texinfo.tex file regardless of its version. Of course that would be nice in theory, but barring a kludge like the above, I don't see how. Perhaps just a failure of imagination. Anyway, I don't think it is so unreasonable for people to avoid using an ancient texinfo.tex with the new texindex. If that causes more old texinfo.tex's to get updated, that's a good thing. k P.S. \gdef\\#1pt{#1}} Indeed. I wish Knuth hadn't done that (it was one of the last changes he ever made to plain.tex), but of course it was never up to us and certainly isn't going to change now.