PS: Please note that I have submitted a patch to XeTeX upstream some 1,5 years ago that (among others) contains a check for outlines fonts in the font list returned by fontconfig and that could easily get extended to also check for the font format: Rev 1: http://tug.org/pipermail/tlbuild/2015q3/003287.html Rev 6: http://tug.org/pipermail/tlbuild/2015q3/003296.html - Fabian