Content Warning equivalent feature should be on Hubzilla
Mastodon has a Content Warning (CW) feature. I've seen it being suggested by others when users want to post anything controversial. It's said to help in keeping the fediverse a healthy place.
The idea behind it is simple. When you add CW to a post, the whole post is not shown by default. You get a short summary of what you're about to say controversial (or possibly annoying?) about, and get a "Show More" button. If anyone's interested to listen to you just seeing that summary, they can click the button and see the rest of the post.
Here's how it works on Mastodon, just for reference:
People have used this feature creatively for posting spoilers, surprises, jokes etc.
Similar thing should be available on Hubzilla.
I tried summary-details HTML tags on a post, in a hope if it works. But it gets stripped and shown as plain text. However, I don't know how this is going to be implemented (bbcode/html/markdown) but summary-details tags seem like a good option to use under the hood. It's implemented by browsers, so shouldn't need JS and should be optimized for performance.
EDIT: Minor word changes