It's "code analysis warning", not "exception" of course!
Can't I edit my own postings anywhere ? There's no edit button on this page :(

This would indeed ease the task of reading and parsing the output log file.

However, a project build is a multi-step process involving various different tools including special purpose customer scripts that all produce some sort of output.

It may be difficult to create a contiguous XML file with a valid syntax from the output of all those processes. So, plain text is the smallest common denominator.