Are there any definitions for the CSV Profiler?

When using the CSV profiler to capture stats, I have some 100+ columns, and I was wondering if there is any documentation that includes descriptions or definitions on these keywords?
My team and I are curious about what the CPUUsage_Process/Idle metric is measured in.

Also GameThread is read to show the performance data coming from the C++ and Blueprint operations… are there any other keywords or categories that specify which could be the problem?

In other words, is there a keyword that shows if the C++ or the Blueprint is a potential performance culprit?