It is not clear what is 'CPU sample' in timeline and how it works.

Question mark with link to documentation, that explains what it is, how it works, how they look on timeline, and why it may be needed, would help.

No file or test is named; start at the timeline CPU sample UI shown in the screenshot and inspect how existing help links are handled. Add documentation linked from a question-mark control that explains CPU samples, how they work, how they appear on the timeline, and why they are useful. Done means the link is available in the timeline and covers each requested point.

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