Re: BUG #16277: xmlelement allows invalid XML characters when XML version is set to 1.0

PG Bug reporting form <noreply@postgresql.org> writes:
> The following example:
> SELECT
>   xmlroot (
>      xmlelement (name "test", CHR(26))
>   , version '1.0'
>   )

> Produces xml with the invalid ASCII character 26.

On what grounds do you call it invalid?  What other behavior
would you expect?

            regards, tom lane