> carl@Carls-MBP-2 lilypond % tidy --version > > HTML Tidy for Mac OS X released on 31 October 2006 - Apple Inc. build 6141
This explains the failure, thanks: Your `tidy` version doesn't support HTML 5. I've submitted an MR to catch this. https://gitlab.com/lilypond/lilypond/-/merge_requests/2241 > I didn't see tidy listed as a prerequisite. It is not a prerequisite; it is simply used if available, as an additional aid to the developers. As it turns out, the naive test for checking the presence of the binary is not sufficient; we must also check for a proper version. Please be reminded that up to now *nobody* worked on building the (complete) documentation on the Mac! You are effectively entering new territory (for which I'm very thankful), and there are dragons, as you've already found out. Werner
