"New topic in this category" email notification customization

Use case: migrating hundreds of “email only” users of a now defunct Yahoo Group to a Discourse instance with multiple categories.

Feature request: Allow customization of email footer per category so I can show the “New Topic for this category” email address and, less urgently, a “New Topic for this Category” button.

I expect that this would build on this prior art:

I’m following up on this lonely request from 2015. And I’d be fine with requiring some standard pattern in the New Topic email addresses for each category, e.g.


That’s a good idea! I guess you’d need Add optional_cat_slug to email subject variables for it to work.