Am Fri, 14 Jan 2022 08:44:06 +0100 schrieb Robert Alessi: > Dear List, > > Something happened with today's update. > > Any of the -dev engines fail to compile the attached .dtx file if the > ´doxˇ package is loaded, but I am not sure the failure is caused by > this package. > > (pdf|xe|lua)latex-dev engines seem to bump into \@doc@describe which > is defined in doc-v3beta.sty. the new doc version used in latex-dev incorporates a few ideas of dox, see the documentation. Beside others it now also defines the command \SpecialMacroIndex, and defines it defined \SpecialUsageIndex with it: \def\SpecialUsageIndex{\SpecialMacroIndex}. As dox then does \let\SpecialMacroIndex\SpecialUsageIndex this loops. Probably dox would need a fix here, it should check if \SpecialMacroIndex is already defined. If I change dox to use \@ifundefined{SpecialMacroIndex}{\let\SpecialMacroIndex\SpecialUsageIndex}{} your skeleton compiles. Thanks for trying latex-dev. It helps to identify such problems :-) Ulrike