/usr/share/postgresql/9.6/extension/address_standardizer.control is in postgresql-9.6-postgis-2.3-scripts 2.3.1+dfsg-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 | # address_standardizer extension
comment = 'Used to parse an address into constituent elements. Generally used to support geocoding address normalization step.'
default_version = '2.3.1'
relocatable = true
|