@
Kindle3w_Pdfs - there's a list of libraries that calibre uses
here
I don't know which 3rd party libraries are involved in calibre accessing the 'net. I've seen mention of a sockets library, and afaik python's socket library makes use of the underlying platform sockets library - on Windows I would guess that's winsock.
Curious - why do you have multiple versions of python
installed? I have several packages that I know use Python and/or Qt etc, but they each bundle the versions against which they've been tested, so I have no installed versions of python, Qt, etc as such.
BR