Thanks, great module!
The project description is for Drupal 7, since there's no need to update template files in Drupal 10.
Also, several cool features are not described, since the module offers not only adding classes, but also setting an ID as well as adding multiple key-value attributes.
Visit https://www.drupal.org/project/block_class → and see that the intro text is for Drupal 7, and that several features (id, attributes) are not described:
Block Class allows users to add classes to any block through the block's configuration interface. By adding a very short snippet of PHP to a theme's block.tpl.php file, classes can be added to the parent
<div class="block ...">element of a block.
Block Class allows users to add classes, ID, and key-value attributes in the parent element of any block through the block's configuration interface. This is useful for example with Views, which has a "CSS class" setting for content level, but not the root element of a block. Hooray for more powerful block theming!
Installing the Drupal 8.x / 2.x version
Download with
composer require drupal/block_classand enable the module. That's it!See Documentation in the README → file and a demo of some of the great features.
Installing the Drupal 7.x version
- Enable the module
[...]
Active
2.0
Documentation