openproject/frontend/app/components/work-packages/wp-watcher-button/wp-watcher-button.directive.html

<button ng-click="vm.toggleWatch()" title="{{ vm.buttonTitle }}" ng-disabled="vm.disabled"
        class="button toolbar-icon" ng-class="vm.buttonClass" id="{{ vm.buttonId }}">

  <op-icon icon-classes="button--icon {{vm.watchIconClass}}"></op-icon>

  <span class="button--text" ng-if="vm.showText" ng-bind="vm.buttonText"></span>
</button>