Manual:$wgNoFollowDomainExceptions

Parser: $wgNoFollowDomainExceptions
External links to these domain names (or any subdomains) will not be set to rel="nofollow".
Introduced in version:	1.15.0
Removed in version:	still in use
Allowed values:	(array)
Default value:	[ 'mediawiki.org', ] (1.23+) array() (1.15-1.22)
Other settings: Alphabetical | By function

Details

If this is set to an array of domains, external links to these domain names (or any subdomains) will not be set to rel="nofollow" regardless of the value of $wgNoFollowLinks .

For instance:

$wgNoFollowDomainExceptions = [
    'en.wikipedia.org',
    'wiktionary.org'
];

This would add rel="nofollow" to links to de.wikipedia.org, but not en.wikipedia.org, wiktionary.org, en.wiktionary.org, us.en.wikipedia.org, etc.

See also

• $wgNoFollowLinks
• $wgNoFollowNsExceptions