I stumbled across this solution to add attributes to the read more links of a node.
Need to get out of the Drush mindset and into the Composer mindset when building new Drupal 8 projects. Some useful links that will help explain the process:
I was trying to theme a specific vocabulary and a specific view mode and the suggestions, by default, didn't allow for this. After some searching I came across this article, which mentioned using the hook:
So, I added the function below in my .theme file to make the following template suggestion available: 'taxonomy_term__VOCABULARY__VIEW_MODE'
I was working on a new Drupal 8 site and had a new geolocation view setup to show locations on a Google map. Everything was working well, then I decided I wanted to add a new field to the node and include that field in the view. After adding the field to the view, I decided against using it and deleted the field from the node (before removing it from the view). This, in turn, deleted the entire view, which cost me a days worth of work! I had not exported my configuration prior to adding this field, so I had no way of getting my view back without restoring my database from Time Machine.
I needed to add a 'button' class to a file field link and ran into the following issue:
I was unable to alter the actual anchor within the twig template. So, to workaround the issue, I added the following code to my .theme file.
* Implements template_process_field().
* Implements template_preprocess_taxonomy_term().
* Implements hook_theme_suggestions_alter().
* Implements template_preprocess_node().
Adding placeholder text to a Drupal 8 form element that is the label of the form can be done in your .theme file with the hook template_preprocess_input().