wp-includes/functions.php:5578Flushes all output buffers for PHP 5.2.
function wp_ob_end_flush_all() { $levels = ob_get_level(); for ( $i = 0; $i < $levels; $i++ ) { ob_end_flush(); }}Introduced in 2.2.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/functions.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.