> Since when has the SWF format had "fundamental openness"?
Since approximately the 1st of May, 2008[1]. Adobe publishes a specification of the file format[2], currently at version 10[3]. N.B. The Wikipedia entry suggests[4] that the specification does not exhaustively cover the capabilities of the format.
[1] http://www.adobe.com/aboutadobe/pressroom/pressreleases/2008...
[2] http://www.adobe.com/devnet/swf.html
[3] http://wwwimages.adobe.com/www.adobe.com/content/dam/Adobe/e...