How can I whitelist a class in a theme?

No worries @sam :sunflower:

Thank you for taking this on - no rush at all I’m sure your plate is full :sweat_smile:

I have one last followup question.

Does defining new tags like:

[foo] 
// slides
[/foo]

to be later converted into

<div class="foo">
// slides
</div>

in the cooked output also require a plugin for now?