/usr/share/postgresql/10/extension/prefix.control is in postgresql-10-prefix 1.2.7-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 | # prefix extension
comment = 'Prefix Range module for PostgreSQL'
default_version = '1.2.0'
module_pathname = '$libdir/prefix'
relocatable = true
|