TYPO3 Core

System: php 8.1 and TYPO3 main + 11.5.7

Use custom lib.parseFunc_RTE:

# Add default class to ul list
lib.parseFunc_RTE.externalBlocks.ul.stdWrap{
  HTMLparser = 1
  HTMLparser {
    tags.ul.fixAttrib.class {
      always = 1
      list = ce-bullets
    }
    keepNonMatchedTags = 1
  }
}

Error in FE when rendering an RTE Field with a ul/li list

(1/1) #1476107295 TYPO3\CMS\Core\Error\Exception
PHP Warning: Undefined array key "class" in /var/www/html/public/typo3/sysext/core/Classes/Html/HtmlParser.php line 532