Thanks @MKMaffo and @bruh for your responses. I’d heard about Ruffle in conversation recently, but I hadn’t got around to investigating it yet, so the reminder was much appreciated.
I played around with Ruffle afternoon and was impressed. I have a small archive of swfs to test (games, art, intros, ads, Messenger winks, etc.). Almost all of them worked; one of the games was a bit glitchy but only one failed to display (the sound worked though). Performance was good, and it’s all really quite excellent.
I remember trying Shumway long ago and it couldn’t do much, but then again it never passed the early stages. I’m pleased, great work for all those involved 
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