On for example https://www.mediawiki.org/w/index.php?title=Talk:Compatibility&action=history the
.comment--without-parentheses::before, .mw-changeslist-links::before, .mw-diff-bytes::before, .mw-tag-markers::before, .mw-uctop::before { content: '('; } .comment--without-parentheses::after, .mw-changeslist-links::after, .mw-diff-bytes::after, .mw-tag-markers::after, .mw-uctop::after { content: ')'; }
CSS rules are being loaded via JavaScript, causing a FOUC if the user has JavaScript enabled. With JavaScript disabled, the user does not see any parens at all.

