The Game and Scene view Rendering is happening in the same process that is rendering and processing the Editor around it. The Profiler tries to give as accurate as possible a view into this in a “how would this look in a player” kind of way, which essentially hides the EditorLoop/Editor overhead in the “Other” Category which is (due to an oversight in how the system was designed/“fixed”, see the bug ticket for details) currently not shown in the Chart unless a sample was selected that contributed to that category, or in any child sample.
Besides that, here’s another writeup on timesteps . And yes, I agree, this should be tackled better in Documentation.