Even after I run dpkg-reconfigure fontconfig (and getting the message Regenerating fonts cache... done.), font-related programs such as fc-list, xfontsel, gnome-font-viewer, etc. omit some fonts contained in packages (e.g. xfonts-cyrillic) that I have previously installed (with apt-get).The files for the omitted fonts get installed under /usr/share/fonts, one of the directories specified in my system-wide fonts.conf file.  It's worth noting that, e.g. fc-list does list many other fonts under this directory.Why are these fonts being ignored?EDIT: FWIW, doing xset fp rehash did not help either.
Why are some apt-get-installed fonts being ignored by fc-list, xfontsel, etc?
debian;x11;fonts;fontconfig
There's more than one point:xfonts-cyrillic is a bitmap font and normally not shown with fc-list.bitmap fonts are shown with xlsfontsin turn, that uses the X server's fontpath, which you can see using xset q, e.g.,   Font Path:     /usr/share/fonts/X11/misc,/usr/share/fonts/X11/100dpi/:unscaled,/usr/share/fonts/X11/75dpi/:unscaled,/usr/share/fonts/X11/Type1,/usr/share/fonts/X11/100dpi,/usr/share/fonts/X11/75dpi,built-insThough the manual page says cyrillic is in the default configuration, it is not — until you restart X.  Then you would see something like this:Font Path:  /usr/share/fonts/X11/misc,/usr/share/fonts/X11/cyrillic,/usr/share/fonts/X11/100dpi/:unscaled,/usr/share/fonts/X11/75dpi/:unscaled,/usr/share/fonts/X11/Type1,/usr/share/fonts/X11/100dpi,/usr/share/fonts/X11/75dpi,built-insIf you do not see that, you can always add to the fontpath by adding an Xorg configuration file as noted in Additional font path for Xorg, but no xorg.conf.Once it is in your fontpath, you should be able to see this font using xlsfonts '*cronyx*', e.g.,-cronyx-courier-bold-o-normal--0-0-100-100-m-0-koi8-r-cronyx-courier-bold-o-normal--14-100-100-100-m-80-koi8-r-cronyx-courier-bold-o-normal--17-120-100-100-m-90-koi8-r-cronyx-courier-bold-o-normal--20-140-100-100-m-120-koi8-r-cronyx-courier-bold-r-normal--0-0-100-100-m-0-koi8-r-cronyx-courier-bold-r-normal--14-100-100-100-m-80-koi8-r-cronyx-courier-bold-r-normal--17-120-100-100-m-90-koi8-r-cronyx-courier-bold-r-normal--20-140-100-100-m-120-koi8-r-cronyx-courier-medium-o-normal--0-0-100-100-m-0-koi8-r-cronyx-courier-medium-o-normal--14-100-100-100-m-80-koi8-r-cronyx-courier-medium-o-normal--17-120-100-100-m-90-koi8-r-cronyx-courier-medium-o-normal--20-140-100-100-m-120-koi8-ras well as with xfontsel.