This is the {{anontools}} template.

It lists a number of tools to help investigate a user IP. It is used in MediaWiki:Anontalkpagetext and MediaWiki:Sp-contributions-footer-anon to link to these external sources with the user's IP as a parameter.

Takes the user IP address as a parameter. Like this:

{{anontools|91.198.174.2}}

Renders this:

[WHOIS · rDNS · Traceroute · Geolocate (Alternate) · Tor check · Current blocks · Global contributions] · [RIRs: America · Europe · Africa · Asia-Pacific · Latin America/Caribbean]

If you follow those links you will find out that the IP address used in this example is for a server in Wikimedia's Amsterdam cluster in the Netherlands.

It also works with IPv6:

{{anontools|2602:306:CE65:5740:D956:A711:C1AC:A893}}

Renders this:

[WHOIS · rDNS · Traceroute · Tor check · Current blocks · Global contributions] · [RIRs: America · Europe · Africa · Asia-Pacific · Latin America/Caribbean]