MediaWiki 1.35.0, HeaderTabs 2.0
Solution : change this in HeaderTabs\includes\HeaderTabs.php
49 $tocpattern = '%<div id="toc" class="toc" role="navigation" aria-labelledby="mw-toc-heading"><input type="checkbox" role="button" id="toctogglecheckbox" class="toctogglecheckbox" style="display:none" /><div class="toctitle" lang=".+?" dir="ltr"><h2 id="mw-toc-heading">.+?</h2><span class="toctogglespan"><label class="toctogglelabel" for="toctogglecheckbox"></label></span></div>' . "\n+" . '(<ul>' . "\n+" . '.+?</ul>)' . "\n+" . '</div>' . "\n+" . '%ms';