/usr/share/doc/cl-asdf/examples/stderr is in cl-asdf 2:3.0.3-1.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 | #! /bin/sh
# This script simply writes some text to STDERR, to check and
# make sure that ASDF:RUN-SHELL-COMMAND handles it properly.
echo "Writing to standard error." >& 2
|