How to generate custom codes in E-mail templates?

Hello, I am interested to know the principle behind capturing contents from the SQL database while creating new E-mail templates for OJS. For example, in the notifications E-mail I see code like

You have a new notification from {$siteTitle}

I am interested to know how the name in {$siteTitle} is generated and what its syntax should be - is “{$siteTitle}” directly referring to the SQL database, or this needs to be defined somewhere in OJS first?

I see that in the SQL database there is a table called “site” then another table “site_settings” and inside it there is entry “title” that is captured by the code “{$siteTitle}”. What I do not understand is how to make myself other codes analogous to “{$siteTitle}” based on entries of interest in the SQL table.

Thanks,

These are defined in the PHP code. See this post: