Earlier quoted context omitted.
It does not need to be open source. Just save the plug-in along with your legacy browser and legacy OS and run it all on an emulator. Making it open source is an excuse to allow people to continue flash development in some way.
What if, rather than just play the Flash content, I want to write a tool to convert it to a different format? Or what if I want to port the player to a new platform, or compile it to WASM so I can run it in a browser? There are a lot of things open sourcing Flash would enable that just running it in a VM would not. And also, why do you care if some people _do_ want to continue developing Flash? It's going to get remo…
The argument presented was that open sourcing would allow that little bit of internet history to be preserved. My point is that you don't need source code for that. IMHO we don't want anyone to continue developing flash. Even it's creator has declared EOL for it. I understand there are people who want to mess around with it and do things that are potentially interesting, I object to disguising those desires as a preservation activity.