I'm trying to figure out how to use test warnings but I can't find anything useful in the documentation or source code. I'm appending to $TEST_WARNINGS_OUTPUT_FILE, and judging by https://github.com/bazelbuild/bazel/blob/be21f194ae00d1a21e8e36a6fbb30be9e449086c/src/test/shell/unittest.bash#L263
that's the correct thing to do. But where do these log messages go? They seem to get added to the TestAttempt proto but that's all I could find. I don't see them in Bazel's log output or in the test's output and I don't see an extra output file or any command line options to control this, either. Is this feature even implemented?