The Traceability Matrix report shows the links between the issues of whatever two saved filters on a matrix view.
It allows manage links (create, view and delete) from the matrix itself and also supports pan & zoom with the mouse.
It is available from two locations:
The JIRA top menu Links/Apps > Matrix/Traceability Matrix:
Server/DC
Cloud
The link can be disabled by a JIRA Administrator from the Links Hierarchy installed modules: