/usr/bin/pinq is in qmail 1.06-5.
This file is owned by root:qmail, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 | #!/bin/sh
# WARNING: This file was auto-generated. Do not edit!
/var/lib/qmail/bin/maildir2mbox && exec pine ${1+"$@"}
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