/usr/share/doc/xmlstarlet/examples/docbook1 is in xmlstarlet 1.6.1-2.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 4 | #!/bin/sh
# Generate HTML from given SGML docbook document
./xmlstarlet tr --omit-decl --docbook /usr/share/sgml/docbook/yelp/docbook/html/docbook.xsl sgml/docbook1.sgml | \
./xmlstarlet fo --html --indent-spaces 2
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