In the Agent Configuration History (https://jenkins:8080/computer/<Agent Name>/jobConfigHistory/) you can view the configuration of that agent as XML. When I try to do that, I get an error that tells me the XML file couldn't be parsed correctly.
When viewing at RAW, one can see, that the less than sign isn't parsed correctly.
Instead of the sign itself (<) every less than sign is shown as
But that's really just trivial thing.