When browsing categories you often want to look for something spesific. Let me give a few examples.

Say am looking for a show that is...

...produced by Steven Spielberg
...was created 1989
...that sets in 2010

An example match would be "Back to the Future". That article is
...in [[Category:1985 films]]
...in [[Category:Films produced by Steven Spielberg]]
...in [[Category:Films set in the 2010s]]

An inner joint of multiple categories can return matches

Or consider a list of people from a nationality or occupation. Say I want to pull a list of Physicists that are/were nationals of United States, Switzerland, and Germany

Albert Einstein would be a match.

Such an addition would lead to the abolishment of some of the categories below

[[Category:Albert Einstein| ]]
[[Category:American pacifists]]
[[Category:American philosophers]]
[[Category:American physicists]]
[[Category:American socialists]]
[[Category:American vegetarians]]
[[Category:Academics of the Charles University]]
[[Category:Cosmologists]]
[[Category:Einstein Family]]
[[Category:ETH Zurich alumni]]
[[Category:ETH Zurich faculty]]
[[Category:Fellows of the Leopoldina]]
[[Category:Ashkenazi Jews]]
[[Category:German-American Jews]]
[[Category:German-American scientists]]
[[Category:German immigrants to Switzerland]]
[[Category:German immigrants to the United States]]
[[Category:German-language philosophers]]
[[Category:German Jews]]
[[Category:German Nobel laureates]]
[[Category:German pacifists]]
[[Category:German physicists]]
[[Category:German refugees]]
[[Category:German socialists]]
[[Category:German vegetarians]]
[[Category:Humanists]]
[[Category:Institute for Advanced Study faculty]]
[[Category:Jewish agnostics]]
[[Category:Jewish American scientists]]
[[Category:Jewish American writers]]
[[Category:Jewish pacifists]]
[[Category:Jewish philosophers]]
[[Category:Leiden University faculty]]
[[Category:Members of the ETH Zurich]]
[[Category:Naturalized citizens of the United States]]
[[Category:Nobel laureates in Physics]]
[[Category:Patent examiners]]
[[Category:People associated with the University of Zurich]]
[[Category:People from the Kingdom of Württemberg]]
[[Category:Recipients of the Pour le Mérite (civil class)]]
[[Category:Relativists]]
[[Category:Stateless persons]]
[[Category:Swiss immigrants to the United States]]
[[Category:Swiss humanitarians]]
[[Category:Swiss Jews]]
[[Category:Swiss Nobel laureates]]
[[Category:Swiss pacifists]]
[[Category:Swiss physicists]]
[[Category:Swiss vegetarians]]
[[Category:Theoretical physicists]]
[[Category:Violinists]]
[[Category:Walhalla enshrinees]]
[[Category:Zionists]]
[[Category:Jewish refugees]]

It is a rather long list... It's length can be effectively third with such a tool.

Version: unspecified
Severity: enhancement