CheckUser is an extension for the MediaWiki wiki software.

Wikimedia Checkuser Screenshots

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  User interface; the default first page that you get after choosing Special:CheckUser
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  The results page that you get after checking a specific IP (or IP range).
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  The results page that you get after checking a specific registered account with the "get IPs" option.
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  Log example

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  User interface in German
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  Log example (German)

Checkuser 2.0 Screenshots

See mw:User:Voice of All/CheckUser2.0

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  The Checkuser logfile, who's been checking who?
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  Checkuser whois information, after you check an IP or range.
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  Various checkuser options.