/usr/share/doc/xmlstarlet/examples/sort3 is in xmlstarlet 1.6.1-1.
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
# lower case first
./xmlstarlet sel -T -t -m /root/elem -s A:T:L @name -v @name -n xml/unsorted.xml
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