Support section and adding code

For channels and videos there is a section « Support », where I can post information about monetization. This section supports several elements of Markdown markup.
I have a ready-made HTML monetization form. Tell me, how can I add HTML code to this field so that it works?

Here is an example of such code

<iframe src="" width="423" height="222" frameborder="0" allowtransparency="true" scrolling="no"></iframe>

Since the support field is federated, I’m not sure every instance wants their users to load random scripts in iframes ; that’s the reason why iframes are sanitized out of that field.

However, you are free to create a plugin that transforms your support field on your instance to show that iframe.