/bin/zfgrep is in gzip 1.6-4ubuntu1.
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 7 | #!/bin/sh
bindir='/bin'
case $1 in
--__bindir) bindir=${2?}; shift; shift;;
esac
PATH=$bindir:$PATH
exec zgrep --__bindir "$bindir" -F "$@"
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