I've seen concepts just vanish from Doxygen+Quickbook docs in the past. I thought this was just a limitation. However, looking at the Quickbook docs, I see that there's now a conceptref reference link. So, I put this very simple concept in a header (parser.hpp) to test things: /** \concept non_void */ template<typename T> concept non_void = (!std::same_as<T, void>); Doxygen appears to process it ok, or at least it says in its output that it does. Then I see non_void show up in these files: bin/parser_reference-xml.doxygen bin/parser_reference-xml/index.xml bin/parser_reference-xml/parser_8hpp.xml (I put the concept in this header, parser.hpp) bin/parser_reference-xml/conceptboost_1_1parser_1_1non__void.xml However, when I put [conceptref non_void Non-void.] in a .qbk file, all that shows up in the rendered HTML is "Non-void." (it's not a clickable link). Also, the no_void concept is not in the Doxygen reference for that header. Most frustratingly, concept constraints disappear from constrained templates in the Doxygen reference docs. Is there some special sauce that makes Quickbook+Doxygen process concepts? Is it doing it, but I'm not looking in the right place? Zach