WinAPI :: Are there programs to view the structure of Windows kernel objects?

Question

API

I study WinAPI (according to Petzold's book), it is difficult to give information, and I linger on one topic for a long time, because. all actions are described "abstractly" and vaguely.
It is said that when writing WinAPI, they tried to focus on the OOP approach, but it turned out so-so.
For example, the function - InvalidateRect writes *somewhere* the coordinates of the area that needs to be redrawn.
I'm wondering where exactly this information is recorded.
The book says that if the invalid area changes, and there is already a WM_PAINT message in the queue, then WM_PAINT is not sent, but the coordinates of the invalid area are simply changed, so that the new invalid area is included in it.
I have a handle hwnd, apparently it points to some structure where my window attributes are stored, calling InvalidateRect, the function refers to the window object, and writes the coordinates of the invalid rectangle, which can be obtained by the GetUpdateRect function.
I also heard about a certain table of descriptors, which just connects my descriptor with the real structure of the object. Is it possible to somehow manually refer to these objects to see their structure?
1) In general, this black box approach annoys me, maybe there are ways to find out in more detail the entire window structure that the Windows kernel has?
I tried to watch and read the ReactOS sources, but it doesn't work out very well.
2) Is it possible to read Win95 sources somewhere?
3) What programs did you use while learning WinAPI? Can you advise something?

Answer 1

Search among sysinternals utilities https://docs.microsoft.com/en-us/sysinternals/down...