the Gravity of Python 2

[Nick Cash]

> and "%s" (which is incredibly useful) is not even documented (I suspect it's also not available on all platforms).

The format specifiers available to Python are just whatever is available to the underlying c time.h. 
The manpage for strftime indicates that %s isn't part of the C standard, but part of "Olson's timezone package", which means it's not available on Windows. Your suspicion is unfortunately correct.