But, less than question mark and a space are not a valid XML combination. XML processing instructions cannot begin with a space. Likewise, PHP cannot run commands into the short tags, like <?echo $foo; ?>. So, there really is no collision, it's just grandstanding.
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But, less than question mark and a space are not a valid XML combination. XML processing instructions cannot begin with a space. Likewise, PHP cannot run commands into the short tags, like <?echo $foo; ?>. So, there really is no collision, it's just grandstanding.
I wonder if the XML PI spec says anything about <?= Can you have a PI start with = ? If not, the echo short tag should stay for certain.
'<?=' is invalid XML. '<?' must be followed by a valid XML Name.
See http://www.w3.org/TR/2008/REC-xml-20081126/#sec-pi