Is "UWP" and "Immersive" app the same thing? And if not, what's the difference?

Question

I'm trying to understand the terminology Microsoft is using. When IsImmersiveProcess returns TRUE does it also mean that the process is a UWP app as reported by the TokenIsAppContainer query on its token?

Here's a small code snippet to illustrate what I mean:

HANDLE hProc = ::OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION, FALSE, pid);
if (hProc)
{
    HANDLE hToken;
    if (::OpenProcessToken(hProc, TOKEN_QUERY, &hToken))
    {
        DWORD dwAppContainer = 0;
        DWORD dwDummy = 0;
        if (::GetTokenInformation(hToken, TokenIsAppContainer, &dwAppContainer, sizeof(dwAppContainer), &dwDummy))
        {
            wprintf(L"isUWP=%d\n", dwAppContainer);
        }

        ::CloseHandle(hToken);
    }

    wprintf(L"isImmersive=%d\n", ::IsImmersiveProcess(hProc));

    ::CloseHandle(hProc);
}

In other words, can a process be UWP and not Immersive, and vice versa?

EDIT: Looking inside IsImmersiveProcess API shows the following quite simple logic. Unfortunately NtUserGetProcessUIContextInformation and PROCESS_UICONTEXT_INFORMATION seem to be undocumented. I can only guess that the value 0 stands for "regular" Win32 process and 1 and 2 for immersive app. Not sure what would differ 1 from 2 though?

EDIT2: According to eryksun's find below in comments the NtUserGetProcessUIContextInformation function may've been declared as such:

enum PROCESS_UICONTEXT{
    PROCESS_UICONTEXT_DESKTOP = 0,
    PROCESS_UICONTEXT_IMMERSIVE,
    PROCESS_UICONTEXT_IMMERSIVE_BROKER,
    PROCESS_UICONTEXT_IMMERSIVE_BROWSER
};

enum PROCESS_UI_FLAGS{
    PROCESS_UIF_NONE = 0,
    PROCESS_UIF_AUTHORING_MODE,
    PROCESS_UIF_RESTRICTIONS_DISABLED
};

struct PROCESS_UICONTEXT_INFORMATION{
    PROCESS_UICONTEXT Context;
    PROCESS_UI_FLAGS flags;
};

BOOL WINAPI NtUserGetProcessUIContextInformation(HANDLE hProc, PROCESS_UICONTEXT_INFORMATION* pProcInfo);

Answer 1

"Immersive" is the old name for the UWP apps. It was their initial name on Windows 8 before calling them "metro", "store" and then "universal" app.

Any app coming from the store and based on the new WinRT API is an "immersive" app. Immersive was chosen because the app were executed full screen on Windows 8.

The MSDN documentation is clearing the ambiguity:

IsImmersiveProcess function

Determines whether the process belongs to a Windows Store app.

The MSDN page is available for IsImmersiveProcess

To summarize:

• All the Store/WinRT/UWP applications run in an app container. This is enforce by the OS.
• Legacy win32 apps can choose to run in a app container to improve their security. Each app has to decide what it want.