/usr/share/dbconfig-common/dpkg/postinst.pgsql is in dbconfig-common 2.0.4ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 | dbc_hardcoded_dbtype=pgsql
. /usr/share/dbconfig-common/dpkg/postinst
|