[wluwvrvs] old style numerals with cfr-lm on Debian

one of the ways to get old style (lowercase) numerals in LaTeX is with the cfr-lm package.

\usepackage{cfr-lm}

On Debian (buster and bullseye), this package is in the texlive-fonts-extra package.  however, installing the package with --no-install-recommends (or APT::Install-Recommends "false" in /etc/apt/apt.conf.d ) is insufficient; there are required dependencies among the package's Recommends (a bug).

most of the additional needed packages can be tracked down with apt-file, but one error message is not so obvious:

No file OMLlmm.fd.

! LaTeX Error: This NFSS system isn't set up properly.

the missing file is in the lmodern package with a file name without capitalization.  somehow LaTeX knows to search for file names case-insensitively, even though its error messages give file names with case.

lmodern: /usr/share/texmf/tex/latex/lm/omllmm.fd

the complete set of packages needed for cfr-lm is

apt install --no-install-recommends texlive-fonts-extra texlive-latex-recommended texlive-latex-extra texlive-fonts-recommended lmodern