Hidden taxonomy variables in the system's send email and message action

The system_mail function includes some taxonomy variables but the action settings form's description does not present these. (%term_name, %term_description, %term_id, %vocabulary_name, %vocabulary_description, %vocabulary_id)

remark:
I created an issue (#323325: Hidden variables in the system's send email and messge action). This issue contains two things. This was not the best decision.
Ok, pp don't forget: "Every trip starts with the first small step."