@cmb69: I just came across https://www.php.net/stringable and looking for a reason that the __toString() method was not documented as an interface method led me back to this PR. Was that intentional?

I noted you referred to "commenting out the xi:includes" in your previous comment but it still wasn't clear to me what you meant by that, as I didn't find discussion about commenting that out in any previously resolved comments. Perhaps it wasn't possible to link to magic.xml definition of the __toString() method directly form this context so the alternative was just to leave the list of methods empty?

[…] and looking for a reason that the __toString() method was not documented as an interface method […]

That documentation needs yet to be written (the PR has a respective comment); until this file is in place, the <xi:include> should be commented out, because otherwise the build system shows an error message (this should be fixed at some point, if possible). The linking to the magic methods doesn't work (I've overlooked that when approving), because <function>__toString</function> is not recognized by the build system; that should have been <link linkend="object.tostring">__toString()</link> instead.

Anyhow, a PR would be welcome!