Hi, I just pushed a patch (d07fafed4af9d22044870ae909f0bb82b1412eb6) that makes the ox-html insensitive to the usage of case of the #+language keyword value.
I realize this might be design, as ox-latex is done in the same way. But I don’t see any reason for Org to have an opinion on the case of language, especially since e.g. blocks are not case-sensitive. Should I also make ox-latex and other backends insensitive to case or maybe just remove the aforementioned commit? Rasmus -- If you can mix business and politics wonderful things can happen!