As a result of discussion it was decided to release Views settings as plugins in a 2.x branch: https://www.drupal.org/node/2888275
This represents a considerable change from the 1.x method.
This module comes with a handy random alphanumeric code generator widget . This widget has a setting which allows administrator to set the number of digits that the alphanumeric code will contain for each instance of the field.
This is the Drupal 7.x version of the original 8.x module