I would like to have the behavior where I can run
:Vex<CR> when pressing
<Tab> in normal mode:
nnoremap <Tab> :Vex<CR>
... to open the netrw file tree window and then I would like to close this window when I press
<Tab> again in any other window in this tab. Is there some way how I can get the window ID when opening the netrw window and then close it by its ID in the same tab?