demand-dk
You can edit file: /plugins/system/gavick/layouts/gavick/offcanvas.php
look for this line of code:
<h5 class="offcanvas-title" id="offcanvasExampleLabel">Offcanvas</h5>
change it to:
<h5 class="offcanvas-title" id="offcanvasExampleLabel"><?php echo Text::_('OFF_CANVAS_TITLE'); ?></h5>
Then you can override this language constant: OFF_CANVAS_TITLE
I will pass to our Gavick team for this update as well.