Admin Bar – Customizer Label Change

You can use the get_node function and admin_bar_menu action. Like so,

function edit_customizer_node( $wp_admin_bar ) {
 $customize = $wp_admin_bar->get_node( 'customize' );
 if ( $customize ) {
  $customize->title = __( 'Customize Theme', 'text-domain' );
  $wp_admin_bar->remove_node( 'customize' );
  $wp_admin_bar->add_node( $customize );
 }
}
add_action( 'admin_bar_menu', 'edit_customizer_node', 999 );

This can be placed in your theme’s functions.php file.

This however moves the customizer link last on the admin bar. You need to do some reordering if you want to keep the link on it’s original position.

p.s. You should replace the text-domain with your theme/plugin text-domain. You can use a plugin like Loco Translate to translate your custom text domains, if needed.