Manual:$wgDisableHardRedirects

Page titles and redirects: $wgDisableHardRedirects
Disable redirects to special pages and interwiki redirects, which use a 302 and have no "redirected from" link.
Introduced in version:1.4.1
Removed in version:Still in use
Allowed values:(boolean)
Default value:false

Details

When this variable is true, hard redirects to a special page or to an interwiki link (an interwiki redirect) are disabled and automatically treated as soft redirects. This means that a user who views a page containing such redirect code will not be redirected but instead shown the link to the intended redirect target.

When this variable is false, such redirects use a HTTP 302 and have no "redirected from" link.

Even if this variable is false, interwiki redirects are only allowed for interwiki prefixes with iw_local set to 1 (true).