Creating tags for mail templates OJS 3.0.2.0

Hello,
We would like to add more tags to our e-mail templates such as journal abbreviation, custom ID etc.
What is syntax for creating such tags for existing data in OJS?

Thanks

Parameters are defined as the instance of the mail is created, in whatever caller is creating the mail. For example:

or

Any parameters defined for that instance are used as search-and-replace keys when sending the mail: