As usual, geolocation being a fundraising-related thing (first introduced in 2009), there's only mystery around it. Here's some sparse links:
- Analytics/Geolocation, published in 2014
- Slowness of GeoIP lookup and workarounds
- gerrit:260316 documents the cookie format
- Analytics/Geowiki documents one way to use the geolocation data
- meta:Geonotice (discussing alternatives to current system for regional-level geolocation)
- "ryan lane says that our geoip service is probably not fine grained enough": meta:IRC office hours/Office hours 2012-01-12
- Extension:CentralNotice might happen to contain some information in a far future.
- meta:MaxMindCityTesting was a test of a geolocation DB data provider
- "Can 3rd parties use geoiplookup.wikimedia.org" (like ULS on another MediaWiki installation)? No known problems on WMF end.
- As of 2015, GeoIP information is set by varnish in a cookie, see phabricator:diffusion/OPUP/history/production/templates/varnish/geoip.inc.vcl.erb for more information and gerrit:190964 for an overview of the system.
- As of 2016, the geoiplookup service was shut down.