wp-admin/includes/meta-boxes.php:1228Displays form fields for changing link target.
$linkobjectfunction link_target_meta_box( $link ) { ?><fieldset><legend class="screen-reader-text"><span> <?php /* translators: Hidden accessibility text. */ _e( 'Target' ); ?></span></legend><p><label for="link_target_blank" class="selectit"><input id="link_target_blank" type="radio" name="link_target" value="_blank" <?php echo ( isset( $link->link_target ) && ( '_blank' === $link->link_target ) ? 'checked="checked"' : '' ); ?> /> <?php _e( '<code>_blank</code> — new window or tab.' ); ?></label></p><p><label for="link_target_top" class="selectit"><input id="link_target_top" type="radio" name="link_target" value="_top" <?php echo ( isset( $link->link_target ) && ( '_top' === $link->link_target ) ? 'checked="checked"' : '' ); ?> /> <?php _e( '<code>_top</code> — current window or tab, with no frames.' ); ?></label></p><p><label for="link_target_none" class="selectit"><input id="link_target_none" type="radio" name="link_target" value="" <?php echo ( isset( $link->link_target ) && ( '' === $link->link_target ) ? 'checked="checked"' : '' ); ?> /> <?php _e( '<code>_none</code> — same window or tab.' ); ?></label></p></fieldset><p><?php _e( 'Choose the target frame for your link.' ); ?></p> <?php}Introduced in 2.6.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-admin/includes/meta-boxes.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.