wp-admin/includes/upgrade.php:3682Disables the Link Manager on upgrade if, at the time of upgrade, no links exist in the DB.
function maybe_disable_link_manager() { global $wp_current_db_version, $wpdb; if ( $wp_current_db_version >= 22006 && get_option( 'link_manager_enabled' ) && ! $wpdb->get_var( "SELECT link_id FROM $wpdb->links LIMIT 1" ) ) { update_option( 'link_manager_enabled', 0 ); }}Introduced in 3.5.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-admin/includes/upgrade.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.