Points to the directory where the compiled binaries for this script location are stored. This directory is created automatically if possible. This option is exclusive to Dovecot 2.4. See https://doc.dovecot.org/latest/core/summaries/settings.html#sieve_script_bin_path.

if isPre24 || !hasPigeonhole
then null
else "/tmp/dovecot-%{user|username|lower}"