ActivityPub defines a stream of objects whose content is essentially text, but can include HTML tags. For example, "<p>I <em>really</em> like strawberries!</p>" (wich I take from Example 8 in https://www.w3.org/TR/activitypub/).
In https://cosocial.ca/@evan/111771562317992298, @evan distinguishes short-form text (e.g., Mastodon 500 characters posts) from long-form text (WordPress article entries). Short-form text does not require much markup, but long-form text may require it to share a faithful copy of an article.
Currently, a WordPress blog does not look the same on Mastodon because the HTML elements are changed. For example, @evan blog entry https://evanp.me/2023/12/26/big-fedi-small-fedi/ has the element <h2 class="wp-block-heading">Big Fedy</h2>, which Mastodon shows as <p><strong>Big Fedy</strong></p>. I don't know who changed the original document structure (Mastodon or WordPress) but it appears that the HTML elements were modified to avoid breaking the Mastodon UX. I imagine that if we include SVG code directly on WordPress pages, these code may be complicated to render on Mastodon, even when the browser supports SVG rendering.
@evanprodromou, which HTML fragment is allowed for the content of an ActivityPub object?
