If you run vim -Nu NONE in cmd.exe you have mouse=a and that is why you can change split sizes with your mouse. Try to set mouse= and resize a split, it wouldn't work.
On my linux box mouse is empty by default so I can't resize splits with a mouse.
Help topic :h 'mouse' tells exactly this:
'mouse' string (default "", "a" for GUI ...
In vim, I open a terminal using :term and enter the normal mode using . Then, :Explore does not open the vim's file navigation view, but creates a another split window of the current terminal session.
That is how it should be.
I would like to know why this is happening, and how to fix it. Thank you!
:Explore is provided by built-in netrw plugin. You can ...
The comments by B layer and Ben Knoble were both helpful in finding the answer.
Vim correctly set the shell based on the $SHELL variable, but did not set shellcmdflag appropriately, and that was what the /s was, the default shellcmdflag for cmd.exe, as stated in the :help 'shell' file.
Setting it to -c in my init.vim seems to have solved the problem, and a ...