The add-on implements a new custom field type - Location, allowing to collect location information from your users. It provides the list of countries/areas/cities based on World Cities Database - https://simplemaps.com/data/world-cities and allows admins to custom the list, add, edit and delete any record.
The following custom field holders will support location custom field:
User custom fields
Thread custom fields
Resource manager custom fields
Media gallery custom fields
XenAddons Showcase item fields and review fields by @bob
Location options will be available when creating a new custom field: