/lib/partman/active_partition/85erasepart/do_option is in ubiquity 18.04.14.
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 8 9 10 11 12 13 14 15 16 17 18 19 20 | #!/bin/sh
. /lib/partman/lib/base.sh
. /lib/partman/lib/crypto-base.sh
dev=$2
id=$3
part=$dev/$id
cd $dev
if [ -f $part/skip_erase ]; then
exit 0
fi
open_dialog PARTITION_INFO $id
read_line num id size type fs path name
close_dialog
crypto_wipe_device $path $part "" || true
|