I've been searching for about an hour now, I already feel kinda dumb. Where can I find a download for the NPAPI ? I've skimmed the Gecko Plugin API Reference a little bit, but couldn't find a downloadlink. I also downloaded the Gecko SDK, which eerily was called xulrunner sdk after downloading (??), but Windows-search told me there was no npapi.h in the package.
Where can I downlaod the NPAPI ?
*Edit:
The canonical source for the NPAPI headers is the NPAPI SDK project. The Gecko SDK headers (as well as the headers in the WebKit source) are based on those.