Comment by GlitchMr

Technically there is sarcasm tag in HTML specification, it's one of tags that is specifically handled in https://html.spec.whatwg.org/multipage/parsing.html#parsing-... ('An end tag whose tag name is "sarcasm"').

However, a problem with sarcasm tag is that it wouldn't really help accessibility compared to say saying "Sarcasm:" or something like "(The preceding remark was sarcastic.)".