+>> --lang=XX could be a setup option, with a default value, then the template would be
+
+ <html xmlns="http://www.w3.org/1999/xhtml" lang="<TMPL_VAR LANG>" xml:lang="<TMPL_VAR LANG>">
+
+>>> Yes, that seems reasonable. I guess there's no problem with defaulting
+>>> to en if it can be overridden in the setup. --[[Joey]]
+
+>>>> Yes, english default makes sense. But maybe this option should also be used to define the
+>>>> language used for the messages, ie override the locale?
+>>>> Or just --html-lang=XX, only used by the templates?
+>>>> — NicolasLimare
+