Eli Zaretskii <eliz@gnu.org> writes:

> Perhaps we should by default produce encoding with BOM when XML header
> specifies UTF-16?

I think yes, https://www.w3.org/TR/xml/#charencoding says

    Entities encoded in UTF-16 MUST [...] begin with the Byte Order Mark

By the way, is Bug#8282 the same as this one, or just closely related?
It's talking about sgml-html-meta-auto-coding-function (though maybe
sgml-xml-auto-coding-function is more relevant).  I'm getting a little
confused between all the different *-find/auto-coding-* functions.
There is also nxml-set-auto-coding which seems to be mostly unused.