>>     Thanks for the specifics. Is there a proposal to have SXML built into
>>     R7RS-large?

> I'm not sure what that would mean; SRFIs normally describe procedures
> and syntax, not formats, except as an ancillary.  The MVP would be a
> procedure that wrote core SXML to an output port as XML, I think.

I thought there'd be read/write procedures and possibly a few map/filter
type functions. A basic SXML->XML writer is less than 150 lines of
Scheme:
<https://github.com/srfi-explorations/srfi-from-asciidoc/blob/master/chibi/sxml.scm>