E-mail address of the maintainer of the software making the geocoding requests to the Nominatim server. This is used to contact them in the event of a problem with their usage. See the Nominatim API.
User-Agent string to send with HTTP(S) requests, or %NULL to use the
default user agent, which is derived from the geocode-glib version
and #GApplication:id, for example: geocode-glib/3.20 (MyAppId)
.
As per the Nominatim usage policy, it should be set to a string which identifies the application which is using geocode-glib, and must be a valid user agent string.
The base URL of the Nominatim service, for example
https://nominatim.example.org
.