We have item with some XMLPAth preprocessing steps.
If received value is not XML structure for some reason, item gets unsupported and appears some error in log file:

noname.xml:1: parser error : noname.xml:1: Start tag expected, '<' not foundnoname.xml:1: ERROR 1045 (28000): Access denied for user 'zabbix'@'localhost'

Its no way to clarify what host or items fails with this problem if you have many agent installed.

It would be great to have some wrapping for stderr from XML library to point what host has this step failed.