wp-includes/functions.wp-styles.php:211Checks whether a CSS stylesheet has been added to the queue.
$handlestring$statusstringoptional'enqueued'boolfunction wp_style_is( $handle, $status = 'enqueued' ) { _wp_scripts_maybe_doing_it_wrong( __FUNCTION__, $handle ); return (bool) wp_styles()->query( $handle, $status );}Introduced in 2.8.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/functions.wp-styles.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.