wp-includes/formatting.php:3272Callback to add rel="nofollow" string to HTML A element.
$matchesarraystringfunction wp_rel_nofollow_callback( $matches ) { return wp_rel_callback( $matches, 'nofollow' );}Introduced in 2.3.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/formatting.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.