Sorry @omnitrio - I’m using your ‘Test Topic’ for mine too 
Dunno why I didn’t think of it myself.
So, something like this might come in handy for build guide makers:
<abbr title='Shattered Realm'>SR</abbr>
SR
An abbreviation tag. Lets you mouse over the abbreviated word to see the full word. You have to insert a ««« Go ahead mouse-over it 
Ha.
You have to insert a in-between two words, or more, that would normally have a space there otherwise it will only display one word on the pop-up.
<p>If you want to tell a reader to enter some text <kbd>you can use these kbd tags</kbd> to indicate what to type in.</p>
If you want to tell a reader to enter some text you can use these kbd tags to indicate what to type in.
You can even use the <kbd> tags in your <details>… check out what I did with them in my guide:
[HOW-TO] Use This Forum Effectively
Spiffy.
Other things that ‘work’ in Discourse.
<p>The following word uses a <strike>strikethrough</strike> typeface.</p>
<p>The following word uses a <sup>superscript</sup> typeface.</p>
<p>The following word uses a <sub>subscript</sub> typeface.</p>
<p>I want to drink <del>cola</del> <ins>wine</ins></p>
<p>The following word uses a <big>big</big> typeface.</p>
<p>The following word uses a <small>small</small> typeface.</p>
The following word uses a strikethrough typeface.
The following word uses a superscript typeface.
The following word uses a subscript typeface.
I want to drink cola wine
The following word uses a big typeface.
The following word uses a small typeface.
Alright this was a pain to figure out how to do but I eventually did it. Basically, the ‘Grid Gallery’ button option we have in the editor here to lay out images side-by-side doesn’t work in the ‘Details’. It shows up in the ‘preview panel’ as if it is working but once you commit it, it throws 'em out vertical. Like so:
<details><summary><font size=5><kbd>Screenshots</kbd></font></summary>
<div data-theme-tiles="2">
 
</div>
</details>
Bummer. So I wanted to figure out how make that work. The answer: <table>
<details><summary><font size=5><kbd>Screenshots</kbd></font></summary>
<br>
<table><tr><td>
</td><td>
</td></tr></table>
</details>
There ya have it.