So I've been searching the forum trying to ensure that I can get a button-like icon showing for a walkthrough.
For example, our software has multiple buttons that utilise Font Awesome, but rather than pasting an image of the button in, which can lead people to think it can be clicked, I'd rather use icons and the button name with the same colour, but not have it look like a button so our users can understand that they are looking for something that looks "like this".
Font Awesome on the homepage seems to be supported, as you can see here (outdated in terms of what document you need it placed in, but still relevant), but unfortunately it took a bit of searching/testing to find out what works best.
Essentially, the Guide HTML/code editor strips blank tags, and unsafe tags. So using <i class="fa fa-unlock"><i/> will immediately be stripped, even if Unsafe HTML is allowed (as it's blank).
The workaround I've found, thanks to learning blank tags get stripped (in this post) is to use the <span> tag instead, with a non breaking space inside it.
What was: <span class="btn-green"><i class="fa fa-pencil"></i> Edit</span>
Becomes: <span class="btn-green"><span class="fa fa-pencil"> </span>Edit</span>
Note that the actual space between the </i> and Edit has been removed due to it existing in the Font Awesome span tag.