/lib/partman/choose_method/40swap/choices 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 | #!/bin/sh
. /usr/share/debconf/confmodule
dev=$1
id=$2
db_metaget partman/method_long/swap description
printf "swap\t${RET}\n"
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