nextcloud-mephi/apps/calendar/templates/part.choosecalendar.rowfields.shared.php

<?php
echo '<td width="20px"><input id="active_' . $_['share']['owner'] . '_' . $_['share']['calendar']['id'] . '" type="checkbox" onClick="Calendar.UI.Share.activation(this,\'' . $_['share']['owner'] . '\',' . $_['share']['calendar']['id'] . ')"' . ($_['share']['active'] ? ' checked="checked"' : '') . '></td>';
echo '<td><label for="active_' . $_['share']['owner'] . '_' . $_['share']['calendar']['id'] . '">' . htmlspecialchars($_['share']['calendar']['displayname']) . '</label></td>';
echo '<td style="font-style: italic;">' .  $l->t('shared with you by') . ' ' . $_['share']['owner'] . '</td>';