If either $wgRightsUrl or $wgRightsPage is specified then this variable gives the text for the
link. Otherwise, it will be treated as raw HTML.
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.

$wgRightsText = null;

The text for the rights link is suppose to fallback to $wgRightsPage when it's set, but $wgRightsText is not. But this is not the case, resulting in a broken sentence like below