Unfortunately, the built-in JUnit_Report.xml is NOT customisable at all. You can not change it.
Up until now, a few people have expressed their wishes for the Profile Name to be included in the built-in reports. For example,
- Execution Profile should be reported in the Report.html and exported to PDF
- How to include Username or profile name in the Cucumber report while executing the same test case in test suite collection
But not supported yet.