In Drupal 8, classes that are used in order to implement a content entity (which extend the ContentEntityBase class) have a validate() method that validates the values entered when creating the entity.
A similar method should be introduced in Backdrop and added to EntityInterface.
GitHub Issue #:
6061
Recent comments
This is good enough, but maybe the module maintainer would like to add such a feature.
specific webform permissions
This should be allowed atleast on private files directory. Accepted your answer though.
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