Binary package “xmlcopyeditor” in ubuntu noble

fast, free, validating XML editor

 XML Copy Editor is an XML editor focusing on editing document markup
 languages like DITA, DocBook, WordprocessingML. It features DTD/XML
 Schema/RELAX NG validation, XSLT, XPath, pretty-printing, syntax
 highlighting, folding, tag completion/locking, and a spelling/style check.