/usr/share/doc/xmlstarlet/examples/sel-root is in xmlstarlet 1.3.0-1.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 | #!/bin/sh
echo '<x/>' | ./xmlstarlet sel --root -t -c /
echo '<x/>' | ./xmlstarlet sel --root -t -c / -t -c /
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