Thanks for doing the search :)

 > - 
https://docs.python.org/3/faq/windows.html#is-a-pyd-file-the-same-as-a-dll

Probably not here.

 > - https://docs.python.org/3/using/windows.html#finding-modules

Perhaps it is best to put a new section here like what you posted above 
(but more generic for ctypes and imports), and then link to it from the 
other places?

 > - https://docs.python.org/3/library/os.html?#os.add_dll_directory

e.g. "This function may be used to work around <module not found> errors"

 > - https://docs.python.org/3/extending/windows.html

e.g. "If your extension module relies on any DLLs other than those 
included with Windows or CPython, you will need to include them or else 
users may receive 'module not found' errors. See <this page> for more 
details."

(Some of that text may already be there, been a while since I read that 
one.)

 > Also AFAIK there is no Windows Sphinx tag beyond .. availability::

Yeah, I think I was thinking of a different project. But if it's all in 
Windows-specific sections anyway, and pointing towards the Windows doc 
page, then it won't matter.