Doesn't pretty much every distribution use /usr/share/doc for this and other package documentation at this point?
Sure, many distributions do this, on a per-package per-version basis as far as I know. /usr/share/doc/emacs-21.2, etc. The distribution makers do it all themselves, it's nothing specified in the GNU standards. This would be a pretty huge change for distributions, particularly since many of them have tools to index /usr/share/doc, web servers that serve it out to localhost, etc. They don't have to change anything. All that will happen is, if HTML installation is enabled at installation, it'll also be available under (say) /usr/share/texinfo/html/emacs/ -- just like /usr/share/info. Anyway, on my redhat 9 system, ditto Debian (the two I can easily check), HTML files are not installed for GNU packages -- precisely because, I imagine, there is no standard target to do so, exactly what we're trying to remedy. It's just the ChangeLog, NEWS, README, and other random files from the distribution. Anyway, /usr/share/doc/package-version doesn't solve the cross-manual xref problem, because of the -version and random subdirectory structure.