It may have been defined at one time, but now it's just
function overhead to check on every request.
Change-Id: I05963a0e496e0a960a4feb6877a03e67c5a6fc85
# Check that there is no previous output or previously set up buffers, because
# that would cause us to potentially mix gzip and non-gzip output, creating a
# big mess.
-if ( !defined( 'MW_NO_OUTPUT_BUFFER' ) && ob_get_level() == 0 ) {
+if ( ob_get_level() == 0 ) {
require_once "$IP/includes/OutputHandler.php";
ob_start( 'wfOutputHandler' );
}