The docs I've found on NPAPI plugins explain how to write plugins to be loaded by browsers, but how hard is it to write an application that loads existing NPAPI plugins?
(My ultimate goal here is to find a way to use SWF content inside an application written with Python and wxPython in Linux. I've accomplished this on Windows by using the comtypes module to load the ActiveX Flash player. For Linux, I'm thinking that wrapping the Gnash NPAPI plugin in some C/C++ code and making this a Python extension seems like it would work, albeit a bit convoluted...)