wp-includes/comment.php:3270Default filter attached to pingback_ping_source_uri to validate the pingback's Source URI.
$source_uristringstringfunction pingback_ping_source_uri( $source_uri ) { return (string) wp_http_validate_url( $source_uri );}Introduced in 3.5.1. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/comment.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.