+ // HTML maxlength uses "UTF-16 code units", which means that characters outside BMP
+ // (e.g. emojis) count for two each. This limit is overridden in JS to instead count
+ // Unicode codepoints (or 180 UTF-8 bytes for old schema).
+ // Subtract arbitrary 75 to leave some space for the autogenerated null edit's summary
+ // and other texts chosen by dropdown menus on this page.
+ $maxlength = $oldCommentSchema ? 180 : CommentStore::COMMENT_CHARACTER_LIMIT - 75;
+