I can reproduce this with xelatex, lualatex, and pdflatex. This does not happen with the monolithic texlive package. Interestingly, the files that are directly involved are all the same. All the koma-script files are identical to their counterparts in the monolithic texlive. The monolithic texlive prints this: --8<---------------cut here---------------start------------->8--- (/gnu/store/pllzpxmvcldqq89x6w36w77xnr1p4lav-texlive-texmf-20210325/share/texmf -dist/tex/latex/l3backend/l3backend-pdftex.def) (./komatest.aux) [1{/gnu/store/ pllzpxmvcldqq89x6w36w77xnr1p4lav-texlive-texmf-20210325/share/texmf-dist/fonts/ map/pdftex/updmap/pdftex.map}] (./komatest.aux) ) Output written on komatest.pdf (1 page, 15553 bytes). --8<---------------cut here---------------end--------------->8--- My guess: the argument is the absolute file name of pdftex.map. It doesn’t belong to any real package in the tlpdb, and I’m pretty sure we generate it. However, in this case it must be missing, so that there is no argument to \strip@prefix. -- Ricardo