Subject: bug#20623: XML and HTML files with encoding/charset="utf-8" declaration loose BOM; Coding system is reset from utf-8-with-signature to utf-8 on save

From: Stefan Monnier <[email-masked]>
Date: Fri, 22 May 2015 17:51:07 -0400

>> > What would you expect Emacs to do instead?  It just obeys the stated
>> > encoding, which says nothing about the BOM.  How can Emacs know when
>> > to use utf-8 and when utf-8-with-signature?
>> To the extent that Emacs has seen the BOM when opening the file, it
>> would make sense for Emacs to try and preserve this detail.
> It does.

While there are cases where it does, this bug report is about a case
where it doesn't, IIUC.

        Stefan