Some time back there was an attack on Lemmy where (if I recall correctly) HTML embedded in emoji allowed tokens of users viewing the emoji to get stolen… which included administrators auth tokens. There was much havoc wrecked that evening.

The mitigation for this was “all HTML entities are escaped”. Doesn’t matter where they are - they’re escaped. This sometimes leads to them being doubly escaped when rendering. Less than, ampersand, and greater than all get doubly escaped ( > & < ).