I try to store some .xml like data in string attribute, but it loses all the content inside the <> field. So after some debug work I find the string attribute doesn't support < > symbols at all.
As you can see.

That is strange, Bug 97542 has been logged

This appears to be a UI issue with the houdini panel stripping out what looks like html. The attribute is set properly - you can test with a pythonscript node