I had some time to do a little experiment and it looks like
you can use something similar like the python scripts I’ve used.

to get the path for each root node from File Browser:

def enum_root_pathes(hwnd, lParam):
    if gui.IsWindowVisible(hwnd):
        name = gui.GetWindowText(hwnd)
        if name == 'File Browser':
            h_systreeview32 = gui.FindWindowEx(hwnd, None , 'SysTreeView32', None)
            if h_systreeview32:
                root_nodes = []
                
                hNode = gui.SendMessage(h_systreeview32,
                                        com.TVM_GETNEXTITEM,
                                        com.TVGN_ROOT,
                                        0)
                while hNode:
                    root_nodes.append(hNode)
                    nextNode = gui.SendMessage(h_systreeview32,
                                               com.TVM_GETNEXTITEM,
                                               com.TVGN_NEXT,
                                               hNode)
                    hNode = nextNode

                for node in root_nodes:
                    tvitem, extras = gui_struct.EmptyTVITEM(node)
                    res = gui.SendMessage(h_systreeview32,
                                          com.TVM_GETITEMW,
                                          0,
                                          tvitem)
                    if res:
                        _, _, _, _, _, _, _, param = gui_struct.UnpackTVITEM(tvitem)                
                        x = ctypes.c_wchar_p.from_address(param)
                        print(ctypes.wstring_at(x))
                return
    return True
gui.EnumChildWindows(notepad.hwnd, enum_root_pathes, None)

To switch to a know/active tab in a docked dialog

NPPM_DMMVIEWOTHERTAB = 1024+1000+35
gui.SendMessage(notepad.hwnd,
                NPPM_DMMVIEWOTHERTAB,
                0, 
                'Python',)

to enumerate the current open tabs of docked dialogs,
I had only partial success. It looks like either the docking manager
corrupts the tab structure, there is a bug in SysTabControl or, likely,
I haven’t understood how to use it correctly.

def enum_tabs(hwnd, lParam):
    if gui.IsWindowVisible(hwnd):
        window_name = gui.GetWindowText(hwnd)
        # class_name = gui.GetClassName(hwnd)
        # if class_name != 'Scintilla':
            # print(window_name, class_name)
        if window_name == 'Tab1':
            open_tabs = gui.SendMessage(hwnd, com.TCM_GETITEMCOUNT, 0,0)
            for i in range(open_tabs):
                # tcitem, extras = create_TCITEM_structure()
                tcitem, extras = create_TCITEMHEADER_structure()
                # res = gui.SendMessage(hwnd, com.TCM_SETCURSEL, i, 0) 
                # print('res', res)
                res = gui.SendMessage(hwnd, com.TCM_GETITEMW, i, tcitem)
                if res:
                    _, _, _, pszText, _, _, = struct.unpack('IiiPii', tcitem)
                    print(i, gui.PyGetString(pszText))
            return
    return True

gui.EnumChildWindows(notepad.hwnd, enum_tabs, None)

This correctly identifies the number of tabs used but it only reports
the tab caption for the last dialog attached to the tab control.
Maybe helpful anyway.

there is no builtin npp message which can be used but for

1. enumerate the child windows for File Browser and then find its SysTreeView32 and us TVM messages to get the needed information
   and for
2. should be the same, enumerate to find your console window and get its associated systabcontrol …