Dear Maintainer,
On bookworm, the last few apt dist-upgrade runs have ended with the diagnostic "install-info: warning: no info dir entry in `/usr/share/info/singular.info'".  dpkg-query -S singular.info reports that singular-doc provides this file.  apt reinstall singular-doc ends with the same diagnostic.

Interestingly, the file /usr/share/info/singular.info exists and starts
    This is singular.info, produced by makeinfo version 4.13 from
singular.tex.

    This is the texinfo file describing Singular (version 4.3.1)
and goes on for about 6.2 MB.  Oddly, this is the only info file in that directory that is not an .info.gz...  (I can't verify that gzip /usr/share/info/singular.info worked because apt dist-upgrades are NO-OPs for me right now.)

Hi Eric, thanks for your report.

The info for singular comes uncompressed because singular itself may read it.
Unfortunately singular can only read it uncompressed. Previously this singular.info
file was somewhere in the doc. The info file has been in the proper place
since version 1:4.3.0-p1+ds-1 (then in experimental).
Therefore fixing this issue requires to implement a z-read machinery in singular itself.
I might be easy but heavy to write. A patch is welcome.

Concerning the info dir entry issue, I will have a look to the machinery that seems
to generate the tex source. Thanks for pointing this issue.

Cheers, Jerome