To use the Message module (part of the Message Stack), you need to create 1 or more "Message types". But, when using the page to do so (or edit an existing type), near the bottom of it there is a field labeled "Replacement tokens", empty by default, and with some explanation below it like so:
The Message Stack appears to be a set of 3 Drupal contributed modules, that can be used in a Drupal 7 or 8 site to implement messaging in a Drupal site.
Here are some details about it (from that same link):
The modules have been written with a pluggable architecture that supports customization and extensibility. Each module includes implementation examples that give a hint of the potential use cases and integration with other popular Drupal modules.
How can a Drupal site builder use the power of a Views Bulk Operations (VBO) enabled view to process its views results via custom logic included in some custom Rules Actions and/or Rules Conditions? Whereas these Rules Actions and/or Rules Conditions are to be performed after some Rules Event occurred, and possible some (other) Rules Conditions must be met also?