I'd like to use Email Extension Templates (https://plugins.jenkins.io/emailext-template/)

to create multiple templates, and send them with a `post` directive in my Jenkinsfile, for a Bitbucket Multibranch Source plugin Job.

Whereas I can see how to add such a template in the post build actions of a freestyle project in the "configure" gui (first image), I don't see this field in my job (it's not a freestyle job), and I don't see any documentation about how to specify a template for the Extended Email plugin section in my Jenkinsfile, in the documentation: https://plugins.jenkins.io/email-ext/

I'm assuming the template would need to be called by its name or id, but I don't see such a field in the docs, or in the Snippet Generator in Jenkins, for the extended email plugin (emailext). 

Is there a way to do this?

Thank you