PHP: <br />
<b>Fatal error</b>:  Uncaught Error: Call to undefined function add_filter() in /www/habi.gna.ch/doc/wp-includes/block-supports/elements.php:263
Stack trace:
#0 {main}
  thrown in <b>/www/habi.gna.ch/doc/wp-includes/block-supports/elements.php</b> on line <b>263</b><br />