Manual:$wgRightsText

Details
If either $wgRightsUrl or $wgRightsPage is specified then this variable gives the text for the link. If using $wgRightsUrl then this value must be specified. If using $wgRightsPage then the name of the page will also be used as the link if this variable is not set.

Example
This will render in the footer as:

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