I've modified lines 88-89 of default_sendmap.php in order to translate the buttons labels :
<button type="submit" class="btn btn-primary js-hs-submit"><?php echo JText::_('COM_HOTSPOTS_SEND_MAP_BUTTON'); ?></button>
<button type="submit" class="btn js-hs-cancel"><?php echo JText::_('COM_HOTSPOTS_CANCEL_BUTTON'); ?></button>
Could you add these and the corresponding lines in the .ini languages files for the next release ?
Thanks,
Laurent