WordPress at a glance
action is not described

woocommerce_settings_(id) action-hook . WC 1.0

Usage

add_action( 'woocommerce_settings_(id)', 'action_function_name_1520' );
function action_function_name_1520(){
	// action...
}

Where the hook is called

WC_Admin_Settings::output_fields()
woocommerce_settings_(id)
woocommerce/includes/admin/class-wc-admin-settings.php 272
do_action( 'woocommerce_settings_' . sanitize_title( $value['id'] ) );

Where in WP core the hook is used WooCommerce

woocommerce/includes/admin/class-wc-admin-api-keys.php 21
add_action( 'woocommerce_settings_page_init', array( $this, 'screen_option' ) );
woocommerce/includes/admin/class-wc-admin-webhooks.php 21
add_action( 'woocommerce_settings_page_init', array( $this, 'screen_option' ) );
woocommerce/includes/admin/settings/class-wc-settings-page.php 38
add_filter( 'woocommerce_settings_tabs_array', array( $this, 'add_settings_page' ), 20 );
woocommerce/includes/admin/settings/class-wc-settings-page.php 40
add_action( 'woocommerce_settings_' . $this->id, array( $this, 'output' ) );
woocommerce/includes/admin/settings/class-wc-settings-page.php 41
add_action( 'woocommerce_settings_save_' . $this->id, array( $this, 'save' ) );
woocommerce/includes/admin/settings/class-wc-settings-tax.php 29
add_filter( 'woocommerce_settings_tabs_array', array( $this, 'add_settings_page' ), 20 );
woocommerce/includes/admin/settings/class-wc-settings-tax.php 33
add_action( 'woocommerce_settings_' . $this->id, array( $this, 'output' ) );
woocommerce/includes/admin/settings/class-wc-settings-tax.php 34
add_action( 'woocommerce_settings_save_' . $this->id, array( $this, 'save' ) );
woocommerce/includes/class-wc-register-wp-admin-settings.php 40
add_filter( 'woocommerce_settings_groups', array( $this, 'register_page_group' ) );
woocommerce/includes/class-wc-register-wp-admin-settings.php 43
add_filter( 'woocommerce_settings_groups', array( $this, 'register_email_group' ) );
woocommerce/includes/tracks/events/class-wc-settings-tracking.php 33
add_action( 'woocommerce_settings_page_init', array( $this, 'track_settings_page_view' ) );
woocommerce/packages/woocommerce-admin/src/Features/Navigation/Init.php 29
add_filter( 'woocommerce_settings_features', array( $this, 'add_feature_toggle' ) );
woocommerce/packages/woocommerce-admin/src/Features/Settings.php 47
add_filter( 'woocommerce_settings_features', array( $this, 'add_feature_toggle' ) );
woocommerce/packages/woocommerce-admin/src/Loader.php 76
add_filter( 'woocommerce_settings_groups', array( __CLASS__, 'add_settings_group' ) );