custom module date formatter for publication date I have a Drupal 8 contrib module AP Style Date that provides a formatter for dates to conform to the AP Style Guide date rules. When using the module Publication Date, this formatter does not come up as an option. The AP Style Date does come up in views and in managing field display for other date types. Is there a modification that needs to be made to the AP Style Date module or something in the publication date that needs to be modified?
The publication date module provides a function to define which formatters can be used. I added a patch, which we maintain locally, to add the defined "timestamp_ap_style" format to the options. Optionally, I could have added it inside a custom module, but the patch seemed to make more sense.

 function publication_date_field_formatter_info_alter(array &amp;$info) {
   $info['timestamp']['field_types'][] = 'published_at';
   $info['timestamp_ago']['field_types'][] = 'published_at';
   $info['timestamp_ap_style']['field_types'][] = 'published_at';
 }