wp-admin/includes/upgrade.php:2865Utility version of get_option that is private to installation/upgrade.
$settingstringmixedfunction __get_option( $setting ) { // phpcs:ignore WordPress.NamingConventions.ValidFunctionName.FunctionDoubleUnderscore,PHPCompatibility.FunctionNameRestrictions.ReservedFunctionNames.FunctionDoubleUnderscore global $wpdb; if ( 'home' === $setting && defined( 'WP_HOME' ) ) { return untrailingslashit( WP_HOME ); } if ( 'siteurl' === $setting && defined( 'WP_SITEURL' ) ) { return untrailingslashit( WP_SITEURL ); } $option = $wpdb->get_var( $wpdb->prepare( "SELECT option_value FROM $wpdb->options WHERE option_name = %s", $setting ) ); if ( 'home' === $setting && ! $option ) { return __get_option( 'siteurl' ); } if ( in_array( $setting, array( 'siteurl', 'home', 'category_base', 'tag_base' ), true ) ) { $option = untrailingslashit( $option ); } return maybe_unserialize( $option );}Introduced in 1.5.1. 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.