Adding to the comment css tags

Comment from the answer is no different

Is there a way to add a css tag
For example: comment

<div class="topic-post clearfix comment regular">

No, there is no way to do this. Why would you want to do this? What purpose would it serve?

If the commentary has a distinctive feature, then you can later use it to modify the comments themselves.

If you want to modify the “comments”, you can access the details in the ember model, and do the changes in a plugin.