Follow-up. I tried this script to search all known font files (I manually varied the wildcard). So far I have not found one example of a font file that has an index > 0, but I'm very likely misinterpreting things. for f in `locate .otf`; do i=`fc-match -v "$f" | grep index | cut -c 9`; [[ $i -ne 0 ]] && echo "$f"; done \d