Notice that it's still very much possible to produce SWF files with languages like Haxe http://haxe.org/, and there are frameworks that mimic the Flash drawing API like OpenFL https://www.openfl.org/, there is (or was) a lot of interesting stuff like that happening around.
And, of course, Ruffle[1][2] to play them.
Can't modern Flash compile to HTML5? Can the open alternatives also do that?
I wish SWF became a common HTML5 transpile format.
Flash editor was the magic